Doublets & Triplets Cylindrical Singlets Polarized light carries valuable inormation about the various physical parameters that have been acting on it. Magnetic ields, chemical interactions, molecular structures, and mechanical stress all aect optical polarization. Applications relying on these polarization changes include astrophysics, agricultural production, electric power generation, and molecular biology. states are linear, circular, or elliptical according to the paths traced by electric ield vectors in a propagating wave train. Unpolarized light (such as rom an incandescent bulb) is a combination o all linear, circular, and elliptical states. Randomly polarized light, in reerence to laser output, is composed o two orthogonally linearly polarized collinear beams whose power randomly varies over time. Although random, this radiation is always linearly polarized. Depolarized light is usually linearly polarized light that has been randomized by either temporal or spatial retardation variations across or along the beam. I the various retardations are integrated enough, the beam will appear to be depolarized. The randomization process usually varies the linear polarization in a airly smooth and predictable manner. The two indices o reraction are equal only in the direction o an optic axis within the crystal. The dispersion curve or ordinary rays is a single, unique curve when the index o reraction is plotted against wavelength. The dispersion curve or the extraordinary ray is a amily o curves with dierent curves or dierent directions. Unless it is in a particular polarization state, or the crystalline surace is perpendicular to an optic axis, a ray normally incident on a bireringent surace will be divided in two at the boundary. The extraordinary ray will be deviated; the ordinary ray will not. The ordinary ray index n, and the most extreme (whether greater or smaller) extraordinary ray index n E, are together known as the principal indices o reraction o the material. I a beam o linearly polarized monochromatic light enters a bireringent crystal along a direction not parallel to the optical axis o the crystal, the beam will be divided into two separate beams. Each will be polarized at right angles to the other and will travel in dierent directions. The original beam energy, which will be divided between the new beams, depends on the original orientation o the vector to the crystal. Laser BIREFRINGENCE A bireringent crystal, such as calcite, will divide an entering beam o monochromatic light into two beams having opposite polarization. The beams usually propagate in dierent directions and will have dierent speeds. There will be only one or two optic axis directions within the crystal in which the beam will remain collinear and continue at the same speed, depending on whether the bireringent crystal is uniaxial or biaxial. I the crystal is a plane-parallel plate, and the optic axis directions are not collinear with the beam, radiation will emerge as two separate, orthogonally polarized beams. The beam will be unpolarized where the beams overlap upon emergence. The two new beams within the material are distinguished rom each other by more than just polarization and velocity. The rays are reerred to as extraordinary (E) and ordinary (O). These rays need not be conined to the plane o incidence. Furthermore, the velocity o these rays changes with direction. Thus, the index o reraction or extraordinary rays is also a continuous unction o direction. The index o reraction or the ordinary ray is constant and is independent o direction. unpolarized input beam ordinary ray linearly polarized output beam A unpolarized output beam bireringent material extraordinary ray Double reraction in a bireringent crystal linearly polarized output beam B 12.2 1 Visit Us OnLine! www.mellesgriot.com
The energy ratio between the two orthogonally polarized beams can be any value. It is also possible that all energy will go into one o the new beams. I the crystal is cut as a plane-parallel plate, these beams will recombine upon emergence to orm an elliptically polarized beam. The dierence between the ordinary and extraordinary ray may be used to create bireringent crystal polarization devices. In some cases, the dierence in reractive index is used primarily to separate rays and eliminate one o the polarization planes, or example, in Glan-type polarizers. In other cases, such as Wollaston and Thompson beamsplitting prisms, changes in propagation direction are optimized to separate an incoming beam into two orthogonally polarized beams. QUARTZ WAVEPLATES: OPTICAL ACTIVITY VS BIREFRINGENCE Bireringence is applicable to nonactive crystals, such as calcite, that have a speciic direction and index o reraction exactly equal or the ordinary and extraordinary rays. Active crystals, such as quartz, have no such axis, so there is no direction within the crystal in which the indices o reraction are equal. These types o materials exhibit a phenomenon known as optical activity, whereby the axis o incident, linearly polarized light appears to rotate as it propagates along the optic axis. The optic axis or active crystals is the direction in which the index dierence between the O and E indices is minimum. Melles Griot quartz retardation plates do not use the principle o optical activity to create a phase retardation. Instead, the crystals are cut with the optic axis parallel to the suraces o the plate. When quartz is used in this manner, the retardation is caused by the bireringence o the quartz, not the optical activity o the material. DICHROISM Dichroism is selective absorption o one polarization plane over the other during transmission through a material. Sheet-type polarizers are manuactured rom organic materials imbedded into a plastic sheet. The sheet is stretched, aligning molecules and causing them to be bireringent, and then dyed. The dye molecules selectively attach themselves to aligned polymer molecules, so that absorption is high in one plane and weak in the other. The transmitted beam is linearly polarized. Polarizers made o such material are very useul or low-power and visual applications. The usable ield o view is large (up to grazing incidence), and diameters in excess o 0 mm are available. POLARIZATION BY REFLECTION When a beam o ordinary light is incident at the polarizing angle on a transmissive dielectric such as glass, the emerging reracted ray is partially linearly polarized. For a single surace (with n = 1.50) at Brewster s angle, 0% o the light whose electric vector oscillates parallel to the plane o incidence is transmitted. Only 85% o the perpendicular light is transmitted (the other 15% is relected). The degree o polarization rom a single-surace relection is small. I a number o plates are stacked parallel and oriented at the polarizing angle, some vibrations perpendicular to the plane o incidence will be relected at each surace, and all those parallel to it will be reracted. By making the number o plates within the stack large (more than 25), high degrees o linear polarization may be achieved. This polarization method is utilized in Melles Griot polarizing beamsplitter cubes which are coated with many layers o quarter-wave dielectric thin ilms on the interior prism angle. This beamsplitter separates an incident laser beam into two perpendicular and orthogonally polarized beams. THIN METAL FILM POLARIZERS Optical radiation incident on small, elongated metal particles will be preerentially absorbed when the polarization vector is aligned with the long axis o the particle. Melles Griot inrared polarizers utilize this eect to make polarizers or the near-inrared. These polarizers are considerably more eective than dichroic polarizers. Polarizing thin ilms are ormed by using the patented Slocum process to deposit multiple layers o microscopic silver prolate spheroids onto a polished glass substrate. The exact dimensions o these spheroids determine the optical properties o the ilm. Peak absorption can be selected or any wavelength rom 400 to 3000 nm by controlling the deposition process. Contrast ratios up to,000:1 can be achieved with this method. Singlets Doublets & Triplets Cylindrical Laser Visit Us Online! www.mellesgriot.com 1 12.3
Doublets & Triplets Cylindrical Laser Singlets CALCITE Calcite, a rhombohedral crystalline orm o calcium carbonate, is ound in various orms such as limestone and marble. Since calcite is a naturally occurring material, imperections are not unusual. The highest quality materials, those that exhibit no optical deects, are diicult to ind and are more expensive than those with some deects. Applications or calcite components typically all into three broad categories: laser applications, optical research, and general use. Melles Griot oers most calcite components in several quality grades, to meet those various needs. There is no generally agreed upon set o quality speciications or commercial calcite. Most manuacturers base their quality ratings on U.S. military speciication MIL-G-174B. Since these speciications are actually written or optical glass, they are inadequate to describe completely the quality and perormance o calcite. There are three main areas o importance in deining calcite quality. Spectral Properties Trace amounts o chemical impurities, as well as lattice deects, can cause calcite to be colored, which change absorption. For visible light applications, it is essential to use colorless calcite. For near-inrared applications, material with a trace o yellow is acceptable. This yellow coloration results in a 15% to % decrease in transmission below 4 nm. Waveront Distortion (Striae) Striae, or streaked luctuations in the reractive index o calcite, are caused by dislocations in the crystal lattice. They can cause distortion o a light waveront passing through the crystal. This is particularly troublesome or intererometric applications. Melles Griot uses a simple letter system or classiying the eect o striae in calcite: A Less than / peak-to-peak waveront distortion over the clear aperture. This substantially exceeds MIL Spec Grade A speciied by paragraph 3.3.8.1 in MIL-G-174B. B No more than /4 peak to peak o waveront distortion over the clear aperture. This is essentially equivalent to MIL Spec Grade A. C No more than one wave peak to peak over the clear aperture. This is essentially equivalent to MIL Spec Grade B. Scatter Small inclusions within the calcite crystal account or the main source o scatter. They may appear as small cracks or bubbles. In general, scatter presents a signiicant problem only when the polarizer is being used with a laser. The amount o scatter centers that can be tolerated is partially determined by beam diameter and power. Scatter in Melles Griot calcite is indicated by a simple number designation. Scatter evaluation designators are based on perormance when illuminated with 5-mW red HeNe laser: 0 The material is ree rom any visible scatter centers. 1 Some visible grayness due to scatter. 2 Numerous individually visible scatter centers. MELLES GRIOT CALCITE GRADES Melles Griot has selected the most applicable combinations o calcite qualities, grouped into our grades: Laser Grade that meet both striae category A and scatter category 0. Low-Scatter Grade that meet scatter category 0 and striae category B or C. Optical Grade that meet either combined categories A1 or B1. Standard Grade that meet either combined categories A2 or B2 or C1. Notice that, in all except the laser grade, several categories are encompassed or each grade. Where two or more categories are included in a grade, a component meeting this grade will meet one, but not all, individual categories. For example, a component carrying a quality speciication o optical grade (categories A1 or B1) will exhibit low scatter and have between one-tenth and one-quarter wave o peak-to-peak waveront distortion. 12.4 1 Visit Us OnLine! www.mellesgriot.com
CALCITE OPTICAL POLARIZERS Although many orms o calcite polarizers have been designed, the Glan-Taylor, Glan-Thompson, and Wollaston are the most useul. All Glan-type prisms are designed so that both entrance and exit aces are normal to the intended direction o use. The prism angle has been cut so that the O ray is totally internally relected at the irst ace. In the Glan-Thompson prism, two halves are cemented together. In the Glan-Taylor and Glan-Laser prisms, the two polarizer halves are separated by an air space. Although the air space allows the prisms to handle substantially higher power and greater ultraviolet transmission than cemented prisms, the useul angular ield is reduced and loss caused by internal Fresnel relections is slightly increased. In general terms, the acceptance angle or a Glan-Taylor polarizer is typically 8.5 degrees, and or a Glan- Thompson polarizer, it is 18.5 degrees. Wollaston prisms transmit both linearly polarized beams. The beams, polarized in mutually perpendicular planes, emerge rom the prism in dierent directions. Both beams may be manipulated independently arther down the optical path. APPLICATION NOTE Calcite or Polarizers Calcite is a natural, bireringent material. The calcite miner must understand and search or the calcite outcroppings that are o optical quality. Then, the raw calcite must be internally examined through a small, polished window to determine how the crystal will be cut and used. Finally, the calcite must be cut, ground, and polished at exact angles to its optical axis. These skills are very dierent rom those ound in a more normal optical abrication shop. Melles Griot calcite is mined and manuactured by skilled, careully trained technicians who understand these special requirements. Singlets Doublets & Triplets Cylindrical OPEN TRANSMISSION AND EXTINCTION RATIO The open transmission o a pair o polarizers with their polarization directions parallel to each other is denoted by the quantity H 0. The extinction ratio, or transmission o a pair o polarizers with perpendicular polarization direction, is denoted by the quantity H 90. Laser Visit Us Online! www.mellesgriot.com 1 1
Singlets Available in: Production Quantities Doublets & Triplets Glan-Taylor Polarizing Prisms Cylindrical Melles Griot recommends Glan-Taylor polarizing prisms or applications requiring a high degree o polarization purity, high total transmission, and low-to-medium power requirements: $ Glan-Taylor prisms transmit well rom 350 nm to 2300 nm. $ Calcite prisms are separated by an air space with the transmitted beam incident at Brewster s angle on the airspace interace to minimize relection losses. $ The linearly polarized extraordinary beam is not deviated rom its initial path. When selecting Glan-Taylor polarizing prisms, remember: $ The length-to-aperture ratio is 0.85. The usable, ull angular ield o view is asymmetrical about the mechanical axis, and it varies as a unction o wavelength as shown in the graph. $ The rejected (ordinary) beam is absorbed by the prism housing. Recommended maximum cw power-handling capability o this device is 2 watts. $ The prisms are available coated with a broadband antirelection coating centered at either 550 nm or 830 nm. Append the appropriate coating suix to the product number. ANGULAR FIELD OF VIEW IN DEGREES 15 5 asymmetrical symmetrical 0 215 500 00 1500 WAVELENGTH IN NANOMETERS Glan-Taylor angular ield o view L Laser SPECIFICATIONS: GLAN-TAYLOR POLARIZING PRISMS Wavelength Range: 350 2300 nm Material: Calcite Transmission (Ratio o Total Output to Total Unpolarized Input): ½ (k 1 +k 2 ) = 38% Open Transmission or Pair o Prism Polarizers (H 0 ): >28% Extinction Ratio (H 90 ): <1! 45 Useul Field Angle: See graph Length/Aperture: 0.85 Dimensional Tolerance: 80.25 mm Centration: arc minutes Surace Quality: 80 50 scratch and dig Maximum Operating Temperature: 60ºC Mounting: Cylindrical black anodized aluminum housing; direction o polarization and product number permanently engraved on side o housing 12.6 1 Visit Us OnLine! www.mellesgriot.com 03 PTA Glan-Taylor polarizing prisms A
Single-Layer MgF 2 Antirelection Coatings Center Wavelength (nm) 550 830 Wavelength Range (nm) 400 700 650 10 Glan-Taylor Polarizing Prisms Outside Diameter Grade Maximum Relectance (%) 2.0 2.0 *Parts with the coating /C may have slightly reduced transmission below 4 nm. Call or availability. COATING SUFFIX /A /C* Housing Length L Clear Aperture A PRODUCT NUMBER Singlets Doublets & Triplets Cylindrical Laser Optical 40.0 40.0 14.6 19.6 23.9 14.6 19.6 23.9 15!15! 15!15! 03 PTA 1 03 PTA 3 03 PTA 5 03 PTA 001 03 PTA 003 03 PTA 005 Standard 40.0 14.6 19.6 23.9 Note: For antirelection coated prisms please append coating suix rom coatings table above. Polarizer holders can be ound in Chapter 24, Lens, Filter, and Polarizer Mounts. 15!15! 03 PTA 401 03 PTA 403 03 PTA 405 Laser Visit Us Online! www.mellesgriot.com 1 12.7
Singlets Available in: Production Quantities Doublets & Triplets Glan-Thompson Polarizing Prisms Cylindrical Laser Melles Griot Glan-Thompson polarizing prisms oer increased ield o view and high polarization purity or low-to-medium power requirements: $ Glan-Thompson prisms transmit rom 350 nm to 2300 nm. $ A usable ield o >12 degrees and >24 degrees may be expected rom the and 3 length-to-aperture-ratio prisms. $ The increased ield o view allows system throughput to be increased by maximizing cone angles through the system. $ The linearly polarized extraordinary beam is not deviated rom its initial path. It should be noted that: $ The usable ull angular ield o view is asymmetrical about the mechanical axis, and it varies as a unction o wavelength as shown in the graph. $ The calcite prisms are cemented together. $ The rejected (ordinary) beam is absorbed by the prism housing. Recommended cw maximum power handling capability o this device is 2 watts. $ The prisms are available coated with a broadband antirelection coating centered at either 550 nm or 830 nm. Append the appropriate coating suix to the product number. SPECIFICATIONS: GLAN-THOMPSON POLARIZING PRISMS Wavelength Range: 350 2300 nm Material: Calcite Transmission (Ratio o Total Output to Total Unpolarized Input): ½ (k 1 +k 2 ) = 36% Open Transmission or Pair o Prism Polarizers (H 0 ): >25% Extinction Ratio (H 90 ): <1! 45 Useul Field Angle: See graph Dimensional Tolerance: 80.25 mm Centration: arc minutes Surace Quality: 80 50 scratch and dig Maximum Operating Temperature: 60ºC Mounting: Cylindrical black anodized aluminum housing; direction o polarization and product number permanently engraved on side o housing ANGULAR FIELD OF VIEW IN DEGREES 30 25 L/A = 3.0 15 L/A = 5 350 500 00 1500 WAVELENGTH IN NANOMETERS Glan-Thompson angular ield o view L A 03 PTH Glan-Thompson polarizing prisms 12.8 1 Visit Us OnLine! www.mellesgriot.com
Single-Layer MgF 2 Antirelection Coatings Center Wavelength (nm) 550 830 Wavelength Range (nm) 400 700 650 10 Glan-Thompson Polarizing Prisms Grade Length/Aperture Maximum Relectance (%) 2.0 2.0 *Parts with the coating C may have slightly reduced transmission below 4 nm. Call or availability. Outside Diameter COATING SUFFIX /A /C* Housing Length L Clear Aperture A PRODUCT NUMBER Singlets Doublets & Triplets Cylindrical Laser Optical 3.0 3.0 3.0 3.0 17.0 40.0 17.0 40.0 17.0 40.0 14.5 27.0 39.5 52.0 17.0 32.0 47.0 62.0 14.5 27.0 39.5 52.0 5!5 15!15! 5!5 15!15! 5!5 15!15! 03 PTH 9 03 PTH 1 03 PTH 3 03 PTH 5 03 PTH 118 03 PTH 112 03 PTH 114 03 PTH 116 03 PTH 009 03 PTH 001 03 PTH 003 03 PTH 005 Standard 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 17.0 40.0 17.0 40.0 17.0 40.0 17.0 32.0 47.0 62.0 14.5 27.0 39.5 52.0 17.0 32.0 47.0 62.0 5!5 15!15! 5!5 15!15! 5!5 15!15! 03 PTH 018 03 PTH 012 03 PTH 014 03 PTH 016 03 PTH 409 03 PTH 401 03 PTH 403 03 PTH 405 03 PTH 418 03 PTH 412 03 PTH 414 03 PTH 416 Laser Note: For antirelection coated prisms please append coating suix rom coatings table above. Polarizer holders can be ound in Chapter 24, Lens, Filter, and Polarizer Mounts. Visit Us Online! www.mellesgriot.com 1 12.9
Singlets Available in: Production Quantities Doublets & Triplets Glan-Laser Polarizing Prisms Cylindrical Melles Griot Glan-Laser polarizing prisms provide high polarization purity and have exit ports or the rejected (ordinary) beam. They are ideal or use with lasers that have high output energies. $ The Glan-Laser prisms transmit rom 350 nm to 2300 nm. $ Each polarizer consists o two air-spaced calcite prisms. $ Two exit ports, 180 degrees apart, are provided or use in either or both directions. $ The rejected beam exits at approximately 67 degrees rom the linearly polarized extraordinary beam, which is not deviated rom its initial path. $ Single-layer antirelection coatings are available centered at either 550 nm or 830 nm. Append the appropriate coating suix to the product number. SPECIFICATIONS: GLAN-LASER POLARIZING PRISMS Wavelength Range: 350 2300 nm Material: Optical grade calcite Transmission (Ratio o Total Output to Total Unpolarized Input): ½ (k 1 +k 2 ) = 38% Extinction Ratio (H 90 ): <5! 45 Dimensional Tolerance: 80.25 mm Centration: arc minutes Surace Quality: 80-50 scratch and dig Mounting: Cylindrical black anodized aluminum housing with two exit ports; product number permanently engraved on side o housing exit port L A 67º 03 PGL Glan-Laser polarizing prisms LASER-INDUCED DAMAGE: air space sealed with black glass plates Surace damage at an air-crystal interace, or bulk damage within the crystal structure, may occur i the optical surace is contaminated, or the laser power exceeds the material damage threshold. A single value cannot be placed on damage resistance or calcite, because it is a naturally occurring material. Our Glan-Laser polarizers, tested at Big Sky Laser Technologies, Inc., were ound to withstand between 430 and 630 MW/cm 2, nsec pulse at 64 nm. Values are guidelines and no warranty is implied. Single-Layer MgF 2 Antirelection Coatings Center Wavelength Wavelength Range Maximum Relectance (nm) (nm) (%) 550 830 400 700 650 10 2.0 2.0 *Parts with the coating C may have slightly reduced transmission below 4 nm. Call or availability. COATING SUFFIX /A /C* Glan-Laser Polarizing Prisms Laser Outside Diameter 27 34 40 Housing Length L 17.5 24.5 28.5 Clear Aperture A 15!15! Exit Port Diameter 15 PRODUCT NUMBER 03 PGL 301 03 PGL 303 03 PGL 305 Note: For antirelection coated prisms please append coating suix rom coatings table above. Polarizer holders can be ound in Chapter 24, Lens, Filter, and Polarizer Mounts. 12. 1 Visit Us OnLine! www.mellesgriot.com
Wollaston prisms provide a simple way to split a beam o light into two mutually orthogonal, linearly polarized beams, convenient or double imaging o a single source. $ They oer beam divergence o either 15 or degrees. $ They provide useul transmission rom 350 nm to 2300 nm. When speciying a Wollaston prism, the ollowing points should be considered: $ Two calcite prisms are cemented together. $ The beam separation angle between the orthogonally planepolarized output is wavelength dependent, as shown in the graph. $ Single-layer antirelection coatings are available centered at either 550 nm or 830 nm. Append the appropriate coating suix to the product number. Wollaston Prisms BEAM SEPARATION IN DEGREES 30 25 15 5 WOLLASTON 15 WOLLASTON 350 500 00 1500 WAVELENGTH IN NANOMETERS 03 PPW beam separation Available in: Production Quantities Singlets Doublets & Triplets Cylindrical SPECIFICATIONS: WOLLASTON PRISMS Wavelength Range: 350 2300 nm Material: Optical grade calcite Transmission (Ratio o Total Output to Total Unpolarized Input): (k 1 +k 2 ) = 84% Extinction Ratio (H 90 ): <1! 45 L v Length/Aperture: 1.0 Dimensional Tolerance: 80.25 mm Centration: arc minutes Surace Quality: 80 50 scratch and dig Maximum Operating Temperature: 60ºC A Mounting: Cylindrical black anodized aluminum housing; product number permanently engraved on side o housing Wollaston Prisms Outside Diameter Housing Length L 13.0 18.0 13.0 18.0 Beam Deviation v (degrees) 15 15 03 PPW Wollaston prisms Clear Aperture A 15!15 15!15 PRODUCT NUMBER 03 PPW 001 03 PPW 003 03 PPW 012 03 PPW 014 Laser Note: For antirelection coated prisms please append coating suix rom coatings table at let. Polarizer holders can be ound in Chapter 24, Lens, Filter, and Polarizer Mounts. Visit Us Online! www.mellesgriot.com 1 12.11
Singlets Available in: Production Quantities Doublets & Triplets Beamsplitting Thompson Prism Cylindrical Beamsplitting Thompson prisms provide two orthogonally polarized output beams, separated by 45 degrees. $ The beam separation angle and direction are independent o wavelength throughout the transmission range. $ These prisms provide a high extinction ratio. $ The ordinary beam is transmitted through an escape window; the extraordinary beam is transmitted undeviated. $ Calcite prisms are cemented together. $ Single-layer antirelection coatings are available centered around 550 nm or 830 nm. Append the appropriate coating suix to the product number. SPECIFICATIONS: BEAMSPLITTING THOMPSON PRISMS Wavelength Range: 350 2300 nm Material: Optical grade calcite Transmission (Ratio o Total Output to Total Unpolarized Input): (k 1 +k 2 ) = 84% Extinction Ratio (Extraordinary Beam): <1! 45 Extinction Ratio (Ordinary Beam): <5! 45 Separation Angle: 45º81º Dimensional Tolerances: ±0.25 mm Centration: arc minutes Surace Quality: 80 50 scratch and dig Mounting: Cylindrical black anodized aluminum housing; product number is permanently engraved on side. The 45 degrees diagonal exit ace is on the ront o the mount. dimensions in mm 44.0 45º cut o escape window 32.0 03 PTB 001 beamsplitting Thompson prism Single-Layer MgF 2 Antirelection Coatings Center Wavelength (nm) 550 830 Wavelength Range (nm) 400 700 650 10 Maximum Relectance (%) 2.0 2.0 45º *Parts with the coating /C may have slightly reduced transmission below 4 nm. Call or availability. Beamsplitting Thompson Prism Angular Field (degrees) Clear Aperture COATING SUFFIX /A /C* PRODUCT NUMBER 1681 03 PTB 001 Laser 12.12 1 Visit Us OnLine! www.mellesgriot.com
Two parallel, but laterally displaced, orthogonally polarized output beams are transmitted rom one unpolarized input beam when passing through a Melles Griot beam-displacing prism. I the input beam is linearly polarized, the output can be made to vary continuously and sinusoidally rom one parallel beam to the other by rotating the input polarization angle. $ The ordinary beam is undeviated. $ The extraordinary beam is deviated by 6 degrees within the prism. $ Upon exit, the extraordinary beam is again parallel with the input beam and the exiting ordinary beam. $ Single-layer antirelection coatings are available centered at either 550 nm or 830 nm. Append the appropriate coating suix to the product number. SPECIFICATIONS: BEAM-DISPLACING PRISMS Wavelength Range: 350 nm to 2300 nm Nominal Design Wavelength: 500 nm Material: Optical and low-scatter-grade calcite Transmission (Ratio o Total Output to Total Unpolarized Input): (k 1 +k 2 ) = 84% Extinction Ratio (H 90 ): <1! 45 Dimensional Tolerances: ±0.25 mm Centration: arc minutes Surace Quality: 80 50 scratch and dig Mounting: Cylindrical black anodized aluminum housing; product number and line indicating plane o beam separation engraved on side o housing Beam Displacing Prisms Grade Optical Grade Low-Scatter Grade Outside Diameter Housing Length L 26.0 38.0 26.0 38.0 03 PPD beam displacing prisms BEAM SEPARATION IN MILLIMETERS Center Wavelength (nm) 550 830 Beam Displacement at 500 nm 2.7 4.0 2.7 4.0 8 6 4 2 L Wavelength Range (nm) 400 700 650 10 A 350 500 00 1500 WAVELENGTH IN NANOMETERS Beam displacement Single-Layer MgF 2 Antirelection Coatings Clear Aperture A Available in: Production Quantities Beam-Displacing Prisms beam displacement design wavelength 03 PPD 012 Maximum Relectance (%) 2.0 2.0 03 PPD 001 *Parts with the /C coating may have slightly reduced transmission below 4 nm. Call or availability. COATING SUFFIX /A /C* PRODUCT NUMBER 03 PPD 001 03 PPD 012 03 PPD 301 03 PPD 312 Singlets Doublets & Triplets Cylindrical Laser Note: For antirelection coated prisms please append coating suix rom coatings table above. Polarizer holders can be ound in Chapter 24, Lens, Filter, and Polarizer Mounts. Visit Us Online! www.mellesgriot.com 1 12.13
Singlets Available in: Production Quantities Doublets & Triplets Dichroic Sheet Polarizers Cylindrical Dichroic sheet polarizers are used to subject one o the two orthogonal polarizations (either ordinary or extraordinary) to strong absorption. Melles Griot polarizers are made o a plastic dichroic polarizing sheet sandwiched between selected strain-ree glass plates. $ Dichroic sheet polarizers oer large apertures and acceptance angles. $ They provide excellent extinction ratios and are simple to mount. $ They are suited or low-power applications. $ They are constructed or use in the visible spectrum. SPECIFICATIONS: DICHROIC SHEET POLARIZERS Wavelength Range: 350 650 nm Transmission (Ratio o Total Output to Total Unpolarized Input): ½ (k 1 +k 2 ) = 32% Open Transmission or Pair o Polarizers (H 0 ): % Extinction Ratio (H 90 ): 44 or visible white light, closed pair o polarizers Useul Field Angle: 90º (can be used at grazing incidence) Diameter: 80.25 mm Thickness: t±0.5 mm Surace Quality: 80 50 scratch and dig Mounting: Between two glass discs, hermetically mounted in a black anodized aluminum ring; polarization plane o maximum transmission indicated by engravings on the outside edge Dichroic Sheet Polarizers Outside Diameter 1.6 30.2 41.3 50.8 63.5 82.6 93.0 3.0 119.0 OPTICAL DENSITY 6 5 4 3 2 1 Clear Aperture D 9.0 16.9 26.5 38.4 45.4 58.0 76.0 85.0 94.0 1.0 Thickness t 3.5 3.5 3.5 3.5 3.5 Ring Thickness t e 4.0 4.0 4.5 4.8 5.3 5.6 5.6 6.0 6.0 6.0 For sheet polarizer holders, see Chapter 24, Lens, Filter, and Polarizer Mounts. closed ( 90 ) open ( 0 ) 350 400 450 500 550 600 650 WAVELENGTH IN NANOMETERS PRODUCT NUMBER 03 FPG 019 03 FPG 001 03 FPG 003 03 FPG 005 03 FPG 007 03 FPG 009 03 FPG 011 03 FPG 013 03 FPG 015 03 FPG 017 t e t Optical density or pair o 03 FPG dichroic sheet polarizers Laser mounting ring D 03 FPG dichroic sheet polarizers 12.14 1 Visit Us OnLine! www.mellesgriot.com
APPLICATION NOTE Variable Transmittance Using Two Sheet Polarizers The transmittance T o a single-sheet polarizer in a beam o linearly polarized incident light is given by T=k cos 2 ( v)+k sin 2 ( v) 1 2 where ß is the angle between the plane o polarization o the incident beam (more accurately, the plane o the electric ield vector o the incident beam) and the plane o preerred transmission o the polarizer. The orientation o the plane o preerred transmission is clearly marked by engravings on the mount. The principal transmittances o the polarizer, k 1 and k 2, are both unctions o wavelength. Ideally, k 1 = 1, and k 2 = 0. In reality, k 1 is always somewhat less than unity, and k 2 always has some small but nonzero value. I the incident beam is unpolarized, and the angle ß is redeined to be the angle between the planes o preerred transmission (planes o polarization) o two sheet polarizers in near contact, the transmittance o the pair is given by T pair =k 1 k 2 sin 2 v + (k +k ) cos v. I we deine H = T (90º ) = k k 90 pair 1 2 1 2 1 2 2 2 2 and H = T (0º ) = 1 2 2 0 pair (k 1 +k 2 ) 2 the above ormula can be simpliied to 2 2 T pair = H90sin v +H0 cos v 2 =H +(H 4H ) cos v 90 0 90 The quantity H 90 is called the closed transmittance or extinction ratio, and the quantity H 0 is called the open transmittance. Both quantities are wavelength dependent. Because o the large ranges o open and closed transmission, it is convenient to plot the optical densities corresponding to these transmissions, rather than the transmissions themselves.the open and closed optical densities are deined as ollows: D and D 0 90 =log 1 H 0 =log 1 H unpolarized input beam unpolarized input beam 90. open H 0 1/2(k 1 + k 2 ) closed H 90 1/2(k 1 + k 2 ) Singlets Doublets & Triplets Cylindrical Laser Visit Us Online! www.mellesgriot.com 1 12.15
Singlets Available in: Production Quantities Doublets & Triplets Near-Inrared Polarizers Cylindrical These high-contrast polarizers are metallic thin-ilm devices which provide a high degree o polarization in the near inrared. They consist o a vacuum-deposited thin ilm made up o microscopic prolate metal spheroids all aligned in the same direction on the glass surace. $ These polarizers are useul with low-power red and nearinrared sources such as laser diodes and LEDs. $ The spheroids strongly absorb the component o polarization aligned with the long axis and transmit the component o polarization aligned with the short axis. $ They are more useul than the wire grid-type polarizers which relect the unwanted component o polarization. $ The thin-ilm surace o these devices is protected by a lat piece o glass hermetically sealed in a black anodized aluminum cell. $ These polarizers are thin and most eective or radiation incident perpendicular to their surace. $ Divergent or convergent input cone angles up to degrees can be accepted. $ Advantages include the absence o dead zones within the active area, high contrast ratio over a broad spectral band, large apertures, stability in normal temperature and humidity ranges, and ability to absorb unwanted polarization. SPECIFICATIONS: NEAR-INFRARED POLARIZERS Transmission (Ratio o Total Output to Total Unpolarized Input): ½ (k 1 + k 2 )>% Open Transmission or Pair o Polarizers (H 0 ): >16% Useul Field Angle: 8º about normal Diameter : +0, 40.15 mm Thickness (t c ): 2.7580.2 mm Edge Thickness (t e ): 4.280.15 mm Surace Quality: 80 50 scratch and dig Mounting: Between two glass discs, hermetically mounted in a black anodized aluminum ring; polarization plane o maximum transmission indicated by engravings on the outside edge Near-Inrared Polarizers Wavelength Range (nm) 625 780 Outside Diameter 1.0 40.0 Clear Aperture D.0 15.0 35.0 Extinction Ratio (H 90 ) 2! 43 2! 43 2! 43 2! 43 PRODUCT NUMBER 03 FPI 029 03 FPI 021 03 FPI 023 03 FPI 025 780 1250 1.0 1! 43 03 FPI 009 t e t c.0 40.0 15.0 35.0 1! 43 1! 43 1! 43 03 FPI 001 03 FPI 003 03 FPI 005 D 1250 1550 1.0 1! 43 03 FPI 019.0 15.0 1! 43 03 FPI 012 1! 43 03 FPI 014 40.0 35.0 1! 43 03 FPI 016 Laser 03 FPI near-inrared polarizers Note: For sheet polarizer holders, see Chapter 24, Lens, Filter, and Polarizer Mounts. 12.16 1 Visit Us OnLine! www.mellesgriot.com
PERCENT TRANSMITTANCE 25 open pair typical transmittance curves 15 near-inrared polarizer or 625-780 nm 5 closed pair 600 650 700 750 800 WAVELENGTH IN NANOMETERS POLARIZER MOUNTS Melles Griot post-mounted rotators and holders can provide lexibility in holding polarizers. See Chapter 24, Lens, Filter, and Polarizer Mounts, or more inormation about these products. Singlets Doublets & Triplets Cylindrical PERCENT TRANSMITTANCE 25 15 5 open pair near-inrared polarizer or 780-1250 nm typical transmittance curves closed pair 800 900 00 10 WAVELENGTH IN NANOMETERS 25 typical transmittance curves PERCENT TRANSMITTANCE 15 5 open pair near-inrared polarizer or 1250-1550 nm closed pair 1300 1400 1500 WAVELENGTH IN NANOMETERS 1600 Laser Optical density or pairs o 03 FPI dichroic sheet polarizers Visit Us Online! www.mellesgriot.com 1 12.17
Singlets Available in: Production Quantities Custom Sizes Doublets & Triplets Broadband Polarizing Cube Beamsplitters Cylindrical Broadband polarizing cube beamsplitters separate the s- and p-polarized components o an incident beam into two highly polarized output beams separated by a 90-degree angle. $ A 50/50 split in laser energy is achieved or unpolarized incident light. $ Broadband coatings are oered or operation or 450 nm to 680 nm and 650 nm to 850 nm. $ These are ideal or use in white light and polychromatic beam-combining applications. When using a polarizing cube beamsplitter, remember: $ For polychromatic beam-combining applications, the two incoming beams must have properly oriented polarization states. This can be achieved by using a Melles Griot hal-wave plate to rotate the polarization state o the beam. $ Light is ideally incident on the beamsplitter coating at an angle o 45º ±2º. The Melles Griot prism table, described in Chapter 25, Mirror/Beamsplitter Mounts and Prism Tables, is recommended or accurate positioning o the cube within the beam path. $ Only collimated beams o light can be used. A shear plate may be used to make sure that an expanded laser beam is properly collimated beore striking the cube. The Melles Griot shear plate is described in Chapter 51, Lab Accessories. SPECIFICATIONS: BROADBAND POLARIZING CUBE BEAMSPLITTERS Edge Tolerance: 80.2 mm Principal Transmittance: >95% T or p-polarization <1% T or s-polarization Principal Relectance: >99% R or s-polarization <5% R or p-polarization Transmission (Ratio o Total Straight Through Output to Total Unpolarized Input): ½ (k 1 +k 2 ) = 48% Extinction Ratio: H 90 = k 1 k 2 = 0.01 Beam Deviation: 5 arc minutes Entrance/Exit Surace Flatness: < /8 at 632.8 nm Waveront Distortion: < /4 at 632.8 nm Surace Quality: scratch and dig Material: BK7 grade A ine annealed Coating (All Entrance and Exit Faces): Broadband multilayer antirelector <0.5% R Broadband Polarizing Cube Beamsplitters PRODUCT NUMBER A=B=C Wavelength Range 450 680 nm 650 850 nm C p-polarized s-polarized 5.0.0 12.7.0 25.4 03 PBB 009 03 PBB 001 03 PBB 002 03 PBB 003 03 PBB 005 03 PBB 019 03 PBB 011 03 PBB 012 03 PBB 013 03 PBB 015 Laser A B 38.1 03 PBB 007 03 PBB 017 03 PBB broadband polarizing cube beamsplitters 12.18 1 Visit Us OnLine! www.mellesgriot.com
PERCENT TRANSMITTANCE 0 80 60 40 typical transmittance curves p-plane note: ull vertical scale or s-plane is %. s-plane 400 500 600 700 WAVELENGTH IN NANOMETERS Broadband polarizing cube beamsplitter or 450 680 nm wavelength PERCENT TRANSMITTANCE 0 80 60 40 typical transmittance curves p-plane note: ull vertical scale or s-plane is %. s-plane APPLICATION NOTE Another Broadband Polarizing Beamsplitter Wollaston prisms (see page 12.11) are another broadband device or splitting a beam into its component polarizations. The primary advantages o Wollaston prisms are higher polarization eiciency and broader wavelength perormance. The main disadvantage o Wollaston prisms is that the orthogonally polarized beams do not exit rom the optic perpendicular to each other, and the angle o their separation is wavelength dependent. Singlets Doublets & Triplets Cylindrical 600 700 800 900 WAVELENGTH IN NANOMETERS Broadband polarizing cube beamsplitter or 650 850 nm wavelength Laser Visit Us Online! www.mellesgriot.com 1 12.19
Singlets Available in: Production Quantities Custom Sizes Doublets & Triplets Laser-Line Polarizing Cube Beamsplitters Cylindrical Coated polarization beamsplitters are available or twelve common laser wavelengths, rom ultraviolet to inrared, providing a polarization purity o 98% or better at their design wavelength. For normal incident, monochromatic, unpolarized light: $ The incident beam is separated into two polarized beams which emerge through adjacent aces and in directions 90 degrees apart. $ The beam that passes straight through the cube emerges as linearly p-polarized with the electric ield vector parallel to the plane o incidence. $ The beam that emerges rom the cube at right angles to the incident beam is linearly s-polarized with the electric ield vector orthogonal to the plane o incidence. When used with a linearly polarized monochromatic, incident beam: $ The incident beam is similarly divided. $ The ratio o the emergent beam irradiances depend on the orientation o the incident beam electric ield vector. APPLICATION NOTE Variable Ratio Beamsplitter I a polarizing cube is preceded by a hal-wave retardation plate, the result is a variable ratio beamsplitter or linearly polarized, monochromatic input. The output beam irradiance ratio can be continuously varied rom below 1:49 to above 49:1, or ixed at any value in between, by suitably rotating the hal-wave retarder within its plane. A ratio o 1:1 is easily achieved. For unpolarized, monochromatic input at the intended wavelength, and without the retarder, these beamsplitters always achieve a very accurate 1:1 ratio regardless o beamsplitter orientation. or q = zero I p < 2% I o For greater extinction, each cube can be replaced by a pair o cubes in identical orientation. The resulting extinction ratio will be the square o a single pair. q hal-wave plate I s > 97% I o Laser PRISM TABLES Melles Griot prism tables can provide accurate positioning o cube beamsplitters. See Chapter 25, Mirror/Beamsplitter Mounts and Prism Tables or details. linearly polarized laser beam, irradiance I o q linearly polarized laser beam, irradiance I o 2q hal-wave plate or q = 45 I p > 97% I o I s 2% I o 12. 1 Visit Us OnLine! www.mellesgriot.com
PERCENT TRANSMITTANCE 0 80 60 40 s-plane typical transmittance curves.85.90.95 1.00 1.05 1. 1.15 RELATIVE WAVELENGTH, g = l o / l UV laser-line polarizing cube beamsplitter p-plane SPECIFICATIONS: UV LASER-LINE POLARIZING CUBE BEAMSPLITTERS Edge Tolerance: 80.3 mm Principal Transmittance: >90%T or p-polarization >83%T or p-polarization (or 248 nm only) <5%T or s-polarization Principal Relectance: >95%R or s-polarization <%R or p-polarization Transmission (Ratio o Straight Through Output to Total Unpolarized Input): ½(k 1 +k 2 ) = 46% (43% or 248 nm) Open Straight-Through Transmission o Pair Assuming Unpolarized Input: H 0 = ½(k 2 1 +k 2 2 ) = 41% (34% or 248 nm) Singlets Doublets & Triplets Cylindrical PERCENT TRANSMITTANCE 0 80 60 s-plane 40 typical transmittance curves p-plane.85.90.95 1.00 1.05 1. 1.15 Extinction Ratio or Closed Straight-Through Transmission o Pair, Assuming Unpolarized Input: H 90 = k 1 k 2 = 0.05 Beam Deviation: <5 arc minutes Entrance/Exit Surace Flatness: < /4 at 632.8 nm Waveront Distortion: < /2 at 632.8 nm Surace Quality: scratch and dig Material: UV grade synthetic used silica Coating (All Four Entrance/Exit Faces): Laser-line multilayer antirelector <0.25% R Unused aces are ine ground, and all edges are lightly beveled. RELATIVE WAVELENGTH, g = l o / l Visible and near-ir laser-line polarizing cube beamsplitter LASER-INDUCED DAMAGE: Like most cemented cube beamsplitters, the damage threshold o laser-line polarizing cube beamsplitters is limited primarily by the cement interace. At Big Sky Laser Technologies, Inc., the 03 PBS 127 was tested and ound to withstand up to 0.8 J/cm 2 ±%, nsec pulse (68 MW/cm 2 ) at 355 nm. Values are guidelines and no warranty is implied. UV Laser-Line Polarizing Cube Beamsplitters Wavelength Range (nm) 248 308 351 A=B=C 12.7 25.4 12.7 25.4 12.7 25.4 PRODUCT NUMBER 03 PBS 4 03 PBS 7 03 PBS 114 03 PBS 117 03 PBS 124 03 PBS 127 Laser Visit Us Online! www.mellesgriot.com 1 12.21
Cylindrical Doublets & Triplets Singlets Laser SPECIFICATIONS: VISIBLE/IR LASER-LINE POLARIZING CUBE BEAMSPLITTERS Material: BK7, grade A ine annealed Principal Transmittance: >98%T or p-polarization <1%T or s-polarization Principal Relectance: >99%R or s-polarization <2%R or p-polarization Transmission (Ratio o Straight-Through Output to Total Unpolarized Input): ½(k 1 +k 2 ) = 49% Open Straight-Through Transmission o Pair Assuming Unpolarized Input: H 0 = ½(k 2 1 +k 2 2 ) = 49% Extinction Ratio or Closed Straight-Through Transmission o Pair, Assuming Unpolarized Input: H 90 = k 1 k 2 = 0.01 Dimensions: ƒ80.2 mm Beam Deviation: <5 arc minutes Entrance/Exit Surace Flatness: < /8 at 632.8 nm Waveront Distortion: < /2 at 632.8 nm Surace Quality: 40 scratch and dig Coating (All Four Entrance/Exit Faces): Laser-line multilayer antirelector <0.25% R Unused aces are ine ground, and all edges are lightly beveled. CUSTOM BEAMSPLITTERS Custom beamsplitters can be made with the standard right angle prisms described on page.4.5, in Chapter, Prisms and. Custom coatings or speciic wavelengths rom 248 nm through 1.5 mm are available by special request. Visible/IR Laser-Line Polarizing Cube Beamsplitters Visible Inrared Wavelength Range (nm) 488 514 543 632 670 780 830 1300 1550 ƒ.0.0 25.4 38.1.0.0 25.4 38.1.0 25.4.0 12.7.0 25.4 38.1 5.0.0 12.7.0 25.4 38.1 3.2 5.0.0.0 25.4 3.2 5.0.0 12.7.0 25.4 3.2 5.0.0.0 3.2 5.0.0.0 PRODUCT NUMBER 03 PBS 013 03 PBS 015 03 PBS 017 03 PBS 019 03 PBS 023 03 PBS 025 03 PBS 027 03 PBS 029 03 PBS 033 03 PBS 037 03 PBS 043 03 PBS 044 03 PBS 045 03 PBS 047 03 PBS 049 03 PBS 092 03 PBS 093 03 PBS 094 03 PBS 095 03 PBS 097 03 PBS 099 03 PBS 051 03 PBS 052 03 PBS 053 03 PBS 055 03 PBS 057 03 PBS 061 03 PBS 062 03 PBS 063 03 PBS 064 03 PBS 065 03 PBS 067 03 PBS 071 03 PBS 072 03 PBS 073 03 PBS 075 03 PBS 081 03 PBS 082 03 PBS 083 03 PBS 085 12.22 1 Visit Us OnLine! www.mellesgriot.com
Retardation plates, or phase shiters, including quarter- and hal-wave plates, are used primarily or synthesis and analysis o light in various polarization states. The quarter-wave plate is appropriate or isolators used in laser intererometry, multistage traveling wave laser ampliiers (to prevent stages rom behaving as oscillators), and electro-optic modulators. The simplest retardation plate is a uniaxial crystal cut to include the crystalline optic axis direction. The velocity dierence between ordinary and extraordinary beams, rom an unpolarized beam, within the plate is thereore maximized. As O and E beams traverse the plate, a phase dierence accumulates between these beams proportional to the distance traveled within the plate. At emergence, the O and E beams recombine to orm a second, unpolarized beam. Within the retarder plane, the crystalline optic axis and another axis normal to it are oten called the ast or slow axis, depending on whether the uniaxial crystal is positive or negative. By rotating the retarder slightly about one o these axes, it is possible to adjust the retardation amount. Rotation around the crystalline optic axis increases eective plate thickness. However, because it does not aect the velocity dierence between the O and E rays, accumulated retardation is increased. Rotation around the other axis increases eective plate thickness and reduces the velocity dierence between the O and E rays. The latter eect, which dominates or small rotations, reduces accumulated retardation. A narrowband retarder (or combination o retarders) may be tuned over a limited retardation range at ixed wavelength, or over a limited range o wavelengths at ixed retardation. I plate thickness is such that the phase dierence (retardation o the slow ray by comparison with the ast ray at emergence) is a quarter wavelength, the plate is called a irst-order quarter-wave plate. I the phase dierence at emergence is one hal wavelength, the plate is called a irst-order hal-wave plate*. I the phase dierence at emergence is some multiple o one quarter- or one hal-wavelength, the plate is called a multi-order or higher-order plate. Notice that that these names reer to phase dierence, not physical thickness. Since O and E ray reractive indices o most materials are wavelength dependent, the retardation that accumulates within a plate o speciied thickness is also wavelength dependent. A particular Retardation Plates value o retardation can be precisely achieved or normal incidence at only one speciied wavelength. Mica is superior to quartz in broader-band applications in that its principal reraction indices vary more slowly across the visible spectrum. Thus a retarder made or 550 nm and normal incidence will produce closer to the same retardation at other visible wavelengths than quartz, making it more ideal or broadband visible applications. Crystalline quartz is recommended or higher power applications. It exists in let- and right-handed orms, which cause polarization to rotate in opposite directions. In the case o Melles Griot retardation plates, the orm is typically right-handed. o the O and E rays in quartz rapidly changes rom circular to elliptical even or directions that depart only slightly rom the optical axis. For the ellipse to be even approximately circular, much smaller angles are required. For this reason, devices that depend on circular polarization are eective only in highly collimated light propagating nearly parallel to the optic-axis direction. The ollowing retarder applications assume that monochromatic incident light is collimated and is normally incident upon the plate. They describe typical unctions and uses or retardation plates. POLARIZER HOLDERS Melles Griot polarizer holders, ound in Chapter 24, Lens, Filter, and Polarizer Mounts, provide an ideal mount or retardation plates. They are intended or use with the post-mountable rotators described in Chapter 28, Translation and Rotation Stages. Singlets Doublets & Triplets Cylindrical Laser The term irst-order is taken rom the Handbook o (McGraw- Hill, 1995). The term zero-order is also oten used. Visit Us Online! www.mellesgriot.com 1 12.23
Cylindrical Doublets & Triplets Singlets APPLICATION NOTE Hal-Wave Plate Applications I the retarder is a hal-wave plate (either irst- or multiple-order), and the angle between the electric ield vector in a plane or linearly polarized incident beam and the retarder principal plane is v (acute), the emergent beam (also plane or linearly polarized) will make an acute angle v with the retarder principal plane. Thus the hal-wave plate rotates the polarization plane through an angle 2v. Hal-wave plates are used in laser-line rotators that allow the polarization plane o a laser beam to be continuously adjusted without moving the laser. This can also be accomplished by placing a pair o quarterwave plates, identically oriented, back to back. A hal-wave plate ollowed by a polarizing cube will make a variable ratio beamsplitter or monochromatic, linearly polarized inputs. The hal-wave plate will convert let circularly polarized light into right circularly polarized light, or vice versa, by reversing the direction o propagation. It will also convert let elliptically polarized light into right elliptically polarized light, or vice versa. A pair o hal-wave plates, identically oriented and back to back, make up a ull-wave or tint plate as used in photoelastic stress analysis. Similarly, hal-wave plates can be assembled rom quarter-wave plates. APPLICATION NOTE Quarter-Wave Plate Applications I the retarder is a quarter-wave plate, and the angle v between the electric ield vector o the incident linearly polarized beam and the retarder principal plane is +45 degrees, the emergent beam is circularly polarized as shown in the igure below. Reversing v to 545 degrees reverses the sense o circular polarization. A quarter-wave plate will also transorm circularly polarized into linearly polarized light by reversing the direction o propagation. 45 input polarization plane Laser input polarization plane linearly polarized input crystalline optic-axis direction 2v emergent plane polarized beam with plane o polarization rotated linearly polarized input circularly polarized output crystalline optic-axis direction Hal-wave retardation plate Quarter-wavelength retardation plate 12.24 1 Visit Us OnLine! www.mellesgriot.com
Mica retardation plates are recommended or low-power applications such as tint plates in microscopes, visual stress analyzers, and helium neon lasers because o their relatively high absorption coeicient and occasional homogeneities. Melles Griot oers two types o mica retardation plates: $ Broadband mica retarders (Type 1) are suitable or use in the visible spectrum (400 nm to 700 nm), are centered at 550 nm. $ Laser-line mica retarders (Type 2) are made or any speciic wavelength between 400 nm and 2500 nm. They are exactly quarter-wave or hal-wave at the speciic wavelength or which the retardation tolerance will be /50. The most common laser wavelengths are available directly rom stock. Each mica sheet is cemented between protective glass discs or increased strength. Mica Retardation Plates Broadband Mica Retarders (Type 1) Retardation l/2 l/4 Diameter 30 40 50 30 40 50 Available in: Production Quantities Custom Sizes Thickness t 3.5 3.5 3.5 3.5 PRODUCT NUMBER 02 WRM 021 02 WRM 023 02 WRM 025 02 WRM 027 02 WRM 029 02 WRM 001 02 WRM 003 02 WRM 005 02 WRM 007 02 WRM 009 Singlets Doublets & Triplets Cylindrical SPECIFICATIONS: MICA RETARDATION PLATES Wavelength Range: Type 1: 400 700 nm Type 2: Speciic wavelength between 400 nm and 2500 nm Material: Selected mica sheet Waveront Distortion: 2 at 550 nm Mounting: Cemented between protective glass discs Retardation Tolerance: Type 1: / at 550 nm Type 2: /50 Diameter: 80.25 mm Optic Axis: Crystalline axis direction indicated by pair o diametrically opposed dots crystalline optic axis direction marker dots t glass-mica-glass laminate Laser-Line Mica Retarders (Type 2)* Retardation l/2 l/4 Diameter 30 40 50 30 40 50 Thickness t 3.5 3.5 3.5 3.5 *When ordering laser-line retarders, speciy product number and wavelength required (or example, speciy 02 WRM 011/632.8). Note: Antirelection coatings are not available due to the cemented construction o this type o retardation plate. PRODUCT NUMBER 02 WRM 031 02 WRM 033 02 WRM 035 02 WRM 037 02 WRM 039 02 WRM 011 02 WRM 013 02 WRM 015 02 WRM 017 02 WRM 019 Laser 02 WRM mica retardation plates Visit Us Online! www.mellesgriot.com 1 12.25
Singlets Available in: Production Quantities Custom Sizes Doublets & Triplets Quartz Retardation Plates Cylindrical Laser Melles Griot oers quarter- or hal-wave irst-order or multipleorder plates, which are recommended or high- and low-power laser applications. Multiple-order quartz retarders are made rom a single crystalline plate: $ Retardation is slightly temperature dependent. $ The temperature coeicient o retardance (phase dierence between O and E rays at emergence) is approximately 1.0 nm/ C, as deviated rom C. Retardance decreases as temperature increases. First-order retarders, also called zero-order retarders, are assembled rom pairs o optically contacted crystalline quartz plates: $ The quartz plates have orthogonal optic axis directions; thereore, the roles o the ordinary and extraordinary rays are interchanged in passing rom one plate to the other. $ Net retardation is essentially temperature invariant since both plates are nearly equal in thickness (<0.01 nm/ C). The standard wavelengths carried in stock include many o the most commonly used laser lines, rom 193 nm to 1550 nm. Custom quartz retardation plates are available or speciic wavelengths rom 193 nm to 2300 nm. APPLICATION NOTE Wavelength Eects on Quartz Retardation Plates Due to the high degree o accuracy in the manuacturing o these quartz retardation plates, they should not be used ar outside o their design wavelength. However, they can be used at wavelengths that are close to their design wavelength, depending on which type they are. Multiple-order plates are more susceptible to changes in wavelength and they should not be used more than several nanometers outside o their design wavelength, unless some degree o change in the retardation amount is tolerable. First-order waveplates, which are much less susceptible to wavelength changes, can be used up to ~2% above or below the design wavelength with little eect on the retardation. SPECIFICATIONS: QUARTZ RETARDATION PLATES Wavelength: Speciied by customer Wavelength Range: 193 2300 nm Material: Crystal quartz, c-axis cut Retardation Tolerance: See table below Waveront Distortion: / peak to valley at 632.8 nm Diameter: +0, 40.15 mm Parallelism: 0.5 arc seconds Optic Axis: Normal to acet on circumerence o retarder Surace Quality: scratch and dig AR Coatings: For multiple-order plates, see Chapter 5, Optical Coatings. For irst-order plates, only antirelection V-coatings are available and are supplied by special order only Retardation Tolerance or Various Wavelengths Standard Retardation Wavelengths Laser Tolerance (nm) Source (±) 193 ArF (excimer) l / 0 248 KrF (excimer) l / 0 266 Nd: YAG 4th harmonic l / 0 355 Nd: YAG 3rd harmonic l / 300 364 Ar-ion l / 300 488 Ar-ion l / 400 514 Ar-ion l / 500 532 Nd: YAG 2nd harmonic l / 500 543 HeNe (green) l / 500 632 HeNe (red) l / 500 670 Diode l / 500 780 Diode l / 500 830 Diode l / 500 64 Nd: YAG l / 500 1300 Diode l / 500 1550 Diode l / 500 Note: Retardation plates at other wavelengths are available on special order. 12.26 1 Visit Us OnLine! www.mellesgriot.com
dimensions in mm dimensions in mm optic axis direction optic axis direction optic axis direction 02 WRQ quartz retardation plates, irst order 1 2 Quartz Retardation Plates, First Order* Diameter l/2 l/4 30 Quartz Retardation Plates, Multiple Order* 02 WRQ 023 02 WRQ 027 02 WRQ 031 PRODUCT NUMBER Retardation *Please speciy product number and wavelength when ordering (or example, speciy 02 WRQ 003/632.8). 02 WRQ 003 02 WRQ 007 02 WRQ 011 Diameter PRODUCT NUMBER Retardation l/2 l/4 30 02 WRQ 021 02 WRQ 025 02 WRQ 029 02 WRQ 001 02 WRQ 005 02 WRQ 009 Singlets Doublets & Triplets Cylindrical 02 WRQ quartz retardation plates, multiple order *Please speciy product number and wavelength when ordering (or example, speciy 02 WRQ 001/632.8). HOLDERS FOR WAVEPLATES Melles Griot oers two types o holders or retardation plates. The precision holder uses a micrometer versus a lever on the standard holder. Both holders oer 360-degree rotation with 1-degree resolution. The holders are post mountable with either a 1/4- or M6-threaded post. An assortment o polarizer holder adaptors are available to accommodate various size waveplates. Please see Chapter 24, Lens, Filter & Polarizer Mounts or additional inormation. Laser Visit Us Online! www.mellesgriot.com 1 12.27
Singlets Doublets & Triplets Cylindrical The Soleil-Babinet compensator is a continuously adjustable retardation plate. $ Retardation is wavelength dependent, and varies rom zero up to two ull wavelengths (at 546.1 nm) rom 250 nm to 3500 nm. $ Relative retardation is adjusted by turning a micrometer screw. $ The selected retardation value is constant over the entire working aperture o the compensator. $ The compensator comes with a certiicate o the retardation vs wavelength. The Soleil-Babinet compensator is constructed rom a pair o crystalline quartz wedges stacked one on top o the other. The lower wedge, separated rom the irst by a small air space, is moved by a micrometer screw that varies the eective plate thickness. The retardation exhibited by the emergent beam is proportional to the total thickness o the ixed and eective plates. Melles Griot also oers a nonmagnetic-metal divided-circle rotating mount, 04 SBM 001, which is ideal or orienting the compensator about its optic axis. Soleil-Babinet Compensator and Divided-Circle Rotating Mount 21 22 27 48 dimensions in mm 98 76 23 04 SBC 001 Soleil-Babinet compensator SPECIFICATIONS: SOLEIL-BABINET COMPENSATORS Wavelength Range: 250 3500 nm Materials: Schlieren-ree crystalline quartz and non-magnetic metals Retardation Range: 0 to 4 82% at = 300 nm 0 to 2 81% at = 546 nm 0 to 1 80.5% at = 00 nm 0 to 0.5 80.5% at = 00 nm Retardation Resolution: 0.001 at = 632.8 nm Waveront Distortion: /4 or less at 632.8 nm Clear Aperture: -mm diameter Temperature Limits: 4ºC to +80ºC zero retardation: ixed and eective plate o equal thickness Soleil-Babinet compensator maximum retardation: eective plate thickness exceeds that o ixed plate Laser SPECIFICATIONS: DIVIDED-CIRCLE ROTATING MOUNTS Diameter: 140 mm Calibration: 890º (rom zero at top) in 1 steps Vernier Precision: 83 arc minutes Post Diameter: 12 mm Soleil-Babinet Compensator and Divided Circle Rotating Mount Soleil-Babinet Compensator Divided-Circle Rotating Mount PRODUCT NUMBER 04 SBC 001 04 SBM 001 12.28 1 Visit Us OnLine! www.mellesgriot.com