Thinking ahead: a new era in terahertz research

Transcription

1 Thinking ahead: a new era in terahertz research Dedicated researchers across the world are studying the terahertz (THz) frequency range and the wide range of benefits it offers. THz has the potential to offer vast improvements on the scope and performance of many devices and systems, from avionics to medical instruments, but to date it has proved expensive to research, design and develop systems to harness this potential. Acal BFi are working with suppliers and researchers to provide vital equipment to the THz research and development community. What is terahertz and why does it matter? The THz frequency band is usually considered to sit between the millimetre wave band at ~1mm or 0.3THz and the far infrared band at ~30µm or 10THz. It is often known as the THz gap because of the historic relative inability to research and apply it in comparison to the radio and optical wave bands on either side. Research programmes are currently looking at the ways in which various disciplines can exploit the properties that THz offers, which include the following: Ability to penetrate non-conducting materials. Safer and more accurate method of medical diagnostic imaging than X-rays. Capability to detect objects through clothing or plastic bags. Capability of non-destructive measurement of multi-layered materials. Stability in high-altitude communication applications, particularly satellite applications. Non-destructive and non-ionising. 01

2 Terahertz in relation to the spectral fingerprint Electronics Photonics Radio waves Microwaves Terahertz Infrared Visible Ultraviolet X-rays Gamma rays Radio WiFi, Satellite mobile communications phones Inter-molecular vibration Optical communications Photovoltaics Security and medical diagnostics Radiation Terahertz-wave-spectrum The nature of the THz spectrum means that developing good-quality THz systems is difficult and expensive. It is difficult to generate power in the THz band, and the dual issues of keeping power loss to a minimum whilst finding fabrication methods that yield the best results at this frequency have deterred research in many quarters. Yet the potential that THz offers, together with the constraints now emerging with technologies in both lower and higher frequency bands, has prompted academic research groups and corporate R&D departments to fund serious research into how THz can be applied to improve existing and develop new applications. Non-destructive testing (left). Clip in flour with THz Image (right) 02

3 What could Terahertz do for you? There are many exciting opportunities offered by THz across a wide range of disciplines. Researchers at Osaka University have been using THz spectroscopy to look at the properties of graphene for a range of applications, and a team of researchers in the USA published a paper in ChemPhysChem 2007/8 discussing the potential of THz spectroscopy in biosystems, using the technique to investigate simple and complex biological structures at a molecular level. THz is already used in the Pharmaceutical industry for imaging of the internal structure of tablets. So, whilst THz research is not in its infancy, the growing availability and affordability of undertaking research has seen the number of research projects grow significantly, so we can begin to see the potential applications and implications of introducing THz systems. The particular ability of THz to detect hidden objects without damage and without contact opens a huge range of potential commercial, military and security applications. These include the following. Diagnostic imaging For both medical and dental use, THz offers the potential for safer diagnostic imaging with clearer, more detailed results. In dentistry, THz imaging has been shown to be able to identify different types of tissue in the tooth, resulting in the potential for early detection of enamel damage and tooth decay. Security THz imaging is able to detect concealed items under clothing. It therefore offers a range of potential applications to both military and domestic security operators. THz can penetrate packaging material, clothing and non-metallic objects and produces clear, high-quality images, making it ideal for non-contact security searches. In addition, it is thought that THz could be used in front-line situations both in the military and by emergency services to detect explosives and chemical or biological agents. Food and hygiene Using the ability of THz to penetrate packaging and general objects, food producers can improve their quality processes by checking for foreign objects in food production areas before packaging and dispatch. It can also be used to analyse the water content of food items to predict or detect when food is spoiled. Materials inspection From finding defects in silicon wafers to checking the coating on pharmaceutical tablets, THz offers significant value in the field of materials inspection. It can be used both as a quality control method and as part of the production process, for example ensuring that a layer is the appropriate thickness before it moves on to the next stage of production. This is perhaps one of the biggest potential markets for THz systems. In the medical imaging environment, THz may be used in conjunction with current technologies such as Magnetic Resonance Imaging (MRI) to give professionals a safer, non-invasive and detailed way to look inside our bodies and make quicker, more accurate diagnoses. 03

4 Supporting terahertz research Forecasts for the THz market suggest significant growth over the next ten years. A report, Terahertz Radiation Systems: Technologies and Global Markets, published in July 2013 by BCC Research, predicts that the market will be worth $195.3m by 2018 and will exceed $942m by It also says that whilst astronomy research is currently the largest single application of THz systems, THz imaging is likely to be the most valuable market application in the first instance. Research groups need high-specification, precision instruments to carry out research and to help devise the best ways to bring THz products and systems to the market. At Acal BFi, we support this research with the sourcing and supply of a wide range of specialist equipment, including: table-top fibre-coupled THz spectrometer real-time, integrated THz spectrometer high-sensitivity, real-time, uncooled THz imager THz spectroscopy kit fibre-coupled THz emitter fibre-coupled THz detector THz emitter/detector mounting stage power supply for THz sources, and preamplifier for THz detector. New all fiber spectrometer set-up (courtesy of Ekspla) Jean-Claude Sanudo, Business Development Director for Photonics, says: The Acal BFi team have already delivered a number of ultrafast (either femtosecond or picosecond) lasers to research labs building experimental THz set-ups and are seeing increasing interest for both integrated systems and an extended range of components. We are actively talking to leading suppliers in the field and will shortly come up with very interesting and innovative new products to serve the THz market. Typical Terahertz spectrometer set up (courtesy of Ekspla) 04

5 Transforming technologies with terahertz Over hundreds of years, technologies have become more readily available as the cost of systems and manufacturing have reduced, time-to-market has improved, and studies and experience confirms their usefulness. THz research and development is currently at an exciting stage. Potential applications are clear, the price of some technologies needed to study THz is reducing and more companies are prepared to spend time and money to see how THz can be exploited commercially. As always, the challenge is to make the most of limited budgets, producing results that can form the basis of new research, or furthering understanding of the ways we can harness THz to improve current systems. At each stage, Acal BFi are able to offer the best quality equipment, advice and practical support to help you set up, expand and manage your project from start to finish. 05