Gas, Glass & Light: 25+ years of photonic crystal ibres

Transcription

1 Gas, Glass & Light: 25+ years of photonic crystal ibres Philip Russell Erlangen, Germany

2 26 years ago at CLEO-US

3 2D photonic bandgaps in silica/air PCF 45% air filling fraction index contrast 1:1.46 Birks et al, Electron. Lett. 31, 1941 (1995) 12 normalised frequency ωλ/c full photonic band gaps normalised wavevector along fibre βλ β

4 Solid core photonic crystal fibre (1995) Knight et al: Opt. Lett. 21, 1547 (1996) n core > n cladding hollow channels silica glass Guidance by modified total internal reflection ~100 µm

5 Hollow core PCF (1999) Cregan et al: Science 285, 1537 (1999) n core < n cladding hollow channels silica glass Guidance by anti-resonant reflection or a 2D photonic bandgap in cladding ~100 µm

6 MAKING PCF

7 PCF fabrication: Stacking & drawing

8 stack of glass capillaries ~1 cm

9 University of Bath Group in 2004 University of Bath 12 th October 2004

10 THE FIRST PCF

11 The first guiding photonic crystal fibre Knight et al: Opt. Lett. 21, 1547 (1996) 2.3 µm far-field pattern when carrying green & red light

12 Modified total internal reflection 45% air filling fraction index contrast 1:1.46 Knight et al, Electron.Lett. 31, 1941 (1995) 12 normalised frequency ωλ/c normalised wavevector along fibre βλ dispersion of PCF cladding depends on photonic crystal design β

13 was endlessly single-mode evanescence anti-resonant unit cell Birks et al: Opt. Lett. 22, 961 (1997) resonant unit cell fundamental mode cannot squeeze between air-holes higher-order modes can escape into cladding

14 10,000 TIMES BRIGHTER THAN THE SUN

15 Chromatic dispersion in waveguides bluer faster bluer slower depends hollow core + bulk material = filled core optical modes of hollow waveguides always have anomalous dispersion (geometrical effect) bulk glass or gas typically has normal dispersion (material response) dispersion of filled core combination is the balance of the two

16 Chromatic dispersion of 800 of pure nm core silicapcf Knight et al, Phot Tech Lett, 12, 807 (2000) Dispersion (ps/nm.km) nm PCF (measured) bulk silica anomalous normal Wavelength zero dispersion (µm) can be designed to lie anywhere in this range zero chromatic dispersion (560 nm) bluer = faster bluer = slower zero at ~1300 nm

17 White-light generation in solid-core PCF extreme nonlinear optics Nd:fibre laser & amplifier (1064 nm, 5 ps, W launched) Repetition rate 50 MHz, total SC power 6.5 W Fianium Ltd 6 µm 4.5 mw/nm nm Ranka et al: Opt. Lett. 25, 25 (2000) Dudley et al: Rev. Mod. Phys. 78, 1135 (2006)

18 2016 Philip Russell Deep-UV supercontinuum in ZBLAN PCF Jiang et al: Nat. Phot. 9, 133 (2015) Bright stable spectrum down to 200 nm wavelength 1042 nm, 140 fs, 75 MHz, 13 nj core diameter ~3 µm

19 FIBRES WITH NO CORE

20 Excerpt from a talk (by me) in late 1990s November 1995 The irst photonic crystal ibre was useless because it needed defects 2 µm pitch

21 Coreless PCF guides light when helically twisted Beravat et al: Science Adv. 2, e (2016) 1.26 rad/mm 2.86 rad/mm π rad/mm simulation experiment hole diameter 2.2 µm spacing 5.7 µm wavelength 818 nm

22 Untwisted coreless PCF Beravat et al: Science Adv. 2, e (2016) effective axial index n silica passband of fundamental space-filling modes n = 1 axis

23 Twisted coreless PCF Beravat et al: Science Adv. 2, e (2016) Geometrical increase in path-length with radius: n axial radius 2 effective axial index passband in twisted cladding axis NB: Apparent increase in bulk material refractive index is purely topological

24 Mode is guided on-axis at bottom of passband axial refractive index Beravat et al: Science Adv. 2, e (2016) field-lobes in-phase photonic band-gap cut-off band anti-guiding guiding field-lobes out-of-phase 0 radius A gravitational wormhole for light in helically curved periodic space

25 HOLLOW CORE PCF

26 Guidance by 2D bandgap possible in air 45% air filling fraction index contrast 1:1.46 Birks et al, Electron.Lett. 31, 1941 (1995) Cregan et al: Science 285, 1537 (1999) 12 normalised frequency ωλ/c full photonic band gaps normalised wavevector along fibre βλ dispersion of PCF cladding depends on photonic crystal design β

27 2016 Philip Russell Cregan et al: Science 285, 1537 (1999) NEW AGE CRYSTALS The Economist November 21st 1999 microscope ~25 mm of photonic crystal fibre lamp

28 Anti-resonant reflecting (ARR) hollow-core PCFs Benabid et al: Science 298, 399 (2002) Pryamikov et al: Opt. Exp. 19, 1441 (2011) Yu et al: Opt. Exp. 20, (2012) Debord et al: Opt. Lett. 39, 6245 (2014) Uebel et al: Opt. Lett. 41, 1961 (2016) Frosz et al: Phot. Res. 5, 88 (2017) ~30 µm core d D kagome higher loss (~1 db/m) ultra-broadband (1000s of nm) design of first layer critical 2016 nonlinear gas-light interactions enhanced >10,000 times c.f. focused Gaussian beam

29 Guidance by antiresonant reflection in air 12 45% air filling fraction index contrast 1:1.46 normalised frequency ωλ/c guidance by anti-resonant reflection normalised wavevector along fibre βλ core mode is antiresonant with modes of capillaries in the ring β

30 ARR HC-PCFs are not usually single-mode Trabold et al: Opt. Lett. 39, 3736 (2014) Prism-coupling through the cladding Absence of PBG means that light can pass into core resonance Allows accurate measurement of modal phase indices and loss Modal field patterns can be imaged How to suppress higher order modes?

31 Suppressing HOMs in single-ring ARR-PCF d cap / D core z 1 (J 0 ) / z 1 (J 1 ) = 0.68 Uebel et al:, Opt. Lett. 41, 1961 (2016) thick sheath (n lm 1) 10 4 thin-wall capillaries α lm [db/m] FOM 10 2 FOM 11 = α 11 α 01 α 01

32 Bend loss in single-ring PCFs Frosz et al: Phot. Res. 5, 88 (2017) 01 R cr D = D2 π 2 λ 2 2 u 01 π 2 (d / D) 2 1 d / D cosθ

33 BRIGHT ULTRAVIOLET LIGHT

34 Por olio of ultralumina s products & services Op cal Fibres What we do Design Fabrica on Characteriza on Hollow-core Photonic crystal fibres Applica ons High-power beam delivery fs beam delivery Low latency Gas-filled fibre-based light sources Light Sources Deep UV supercon nuum Tunable deep UV MHz repe on rate, µj energy, sub-50 fs lasers Semiconductor metrology Time-resolved na ve fluorescence detec on Advanced material processing Services Consul ng Development projects Deep-level market & applica on understanding Evalua on of HC-PCF related business cases Fibre development & system integra on

35 A supercon nuum light source for the deep UV Key specifica ons nm spectral range Beam quality M 2 < 1.3 mw/nm power spectral density W level average power Technology Applica ons Spectral pulse broadening in gas-filled hollow-core PCF Semiconductor metrology Adv. material characteriza on Time-resolved fluorescence detec on

36 Pressure-tunable dispersion in ARR-PCF kagome Dispersion (ps 2 /km) long well-controlled path-lengths broadband guidance (for few-cycle pulses) low light-glass overlap (high damage threshold) tunable low anomalous/normal dispersion wavelength (nm) bar 20 bar 10 bar bar pump laser Reviews: PR et al: Nat. Phot. 8, 278 (2014) Travers et al: JOSA B 28, A11-A26 (2011) 0 bar 2 bar argon-filled PCF core diameter 29.6 µm frequency (THz) bluer = slower bluer = faster

37 Ultrashort pulses of DUV/VUV light Joly et al: Phys. Rev. Lett. 106, (2011) N ~ 7 soliton pulse 30 fs, 1 µj; 5 bar of Ar core diameter 26 µm temporal focus 20 deep UV time (fs) soliton compression soliton fission frequency (PHz) zero GVD SPM-driven broadening deep UV dispersive wave length (cm)

38 Tunability by varying pulse, fibre & gas Mak et al: Opt. Exp. 21, (2013) wavelength (nm) 200 visible near-uv deep-uv vacuum-uv intensity (a.u.) Xe Kr Ar Ne frequency (PHz) 1% to 8% conversion from near-ir to vacuum-uv

39 Tunable VUV dispersive wave emission Ermolov et al: Phys. Rev. A., 92, (2015) 21 bar numerical simulation 21 bar 26 bar Coherent ultrashort DW pulses of VUV light generated in Ne-filled HC-PCF (35 fs, 4 µj pump at 800 nm) 28 bar 3.5 µj 28.2 bar 5 µj He-filled HC-PCF: VUV portion of the supercontinuum spectrum (linear scale) Compressible to 500 attoseconds (theory)

40 IMPOSING MOLECULAR ORDER

41 Phase-matching in the vicinity of the ZDP ω ω 0 Bauerschmidt et al: Optica 2, (2015) curvature changes sign at ZDP C w Ω R = Raman frequency Δβ = 2π/Λ coh β β 0 C w zero dispersion point Raman coherence wave C w

42 Pressure-tunable from UV to IR Bauerschmidt et al: Optica 2, (2015) core diameter ~40 µm read 30 bar zero dispersion wavelength 0.43 frequency [THz] bar write W 0 write write read W 1 12 bar read wavelength [µm] (β ref β) [mm 1 ] pressure [bar]

43 Broad-band spectral up-conversion Bauerschmidt et al: Optica 2, (2015) signal to be up-shifted 27.6 bar wavelength (µm) 532 nm writing signal photon rate (db) up-shifted signal frequency (THz)

44 LIGHT-DRIVEN MECHANICAL MOTION

45 guiding beam white light source dichroic mirror Particle launching in hollow-core PCF lack of diffraction means that particle experiences constant acceleration low NA particle loading beam high NA dichroic mirror hollow core PCF laser tweezers pioneer Arthur Ashkin (1922-) camera

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47 Flying (charged) particle microphone Bykov et al: Nat. Phot. 9, 461 (2015) At the keyboard: Maria Bykova Recording engineer: Dmitry Bykov noise caused by Brownian motion quality: not quite as good as a wax cylinder

48 Acknowledgements Ringberg Castle, June

49 Solid core PCF Introduction Hollow core PCF 10,000 times brighter than the sun Bright ultraviolet light Imposing molecular order Glass syrup ultralumina GmbH Light-driven mechanical motion Fibres with no core