Agilent Measurement Journal - Issue 4 - 2008 - (Page 54)

pumped helium bath cryostat (including an 8 T superconducting magnet). All instruments feature optical access, purged and evacuated terahertz time-domain spectroscopy systems — including an ultra-broad bandwidth capability — and on-chip, guided-wave terahertz apparatus. Associated with this facility is a new III-V semiconductor molecular beam epitaxy (MBE) laboratory and a semiconductor nanotechnology cleanroom. The laboratory’s work is presently coordinated by four academic staff who lead a team of approximately 10 post-doctoral workers and 20 Ph.D. students. The main focus is on developing new technology and applications for terahertz spectroscopy. Three major programs are currently underway: spectroscopy of materials with security signiﬁcance (such as drugs-of-abuse and explosives); fundamental investigations of condensed matter systems; and medical imaging and spectroscopy. The recent installation of a state-of-the-art MBE growth facility has enabled successful demonstration of terahertz quantum cascade lasers, which are now being supplied to several groups worldwide, including Harvard University. Figure 1. Research conducted in the University of Leeds Terahertz Photonics Laboratory focuses on developing new technology and applications for terahertz spectroscopy. Agilent-funded research: Terahertz evanescent-ﬁeld microscope John Cunningham University of Leeds The main reason that terahertz application solutions have not become widespread is that terahertz waves are hard to generate, guide and detect. When signiﬁcant progress is made in these areas, broad commercialization should occur, driven by the many unique capabilities of terahertz. In recent years, there has been great progress in the use of terahertz frequency radiation for medical imaging applications. In particular, the potential of pulsed terahertz techniques has been proven in the laboratory diagnosis of basal cell carcinomas, melanomas and dental caries. However, a number of technical challenges must be addressed and overcome before this frequency range can be routinely applied to biological imaging. The two key technical issues to address are the complexity and cost of the terahertz timedomain apparatus and the spatial resolution available. Furthermore, three additional issues are limiting the rate of progress: the lack of a fundamental understanding of the image contrast mechanisms obtained, the nature of the interaction of terahertz radiation with tissue materials and the interplay between radiation of absorption and scattering phenomena in inhomogeneous materials. Nevertheless, there is clear and demonstrated potential for the future industrial development of terahertz imaging systems. Terahertz research at Leeds: An overview The University of Leeds Terahertz Photonics Laboratory, in the School of Electronic and Electrical Engineering, is a dedicated facility for investigating and utilizing terahertz frequency components and systems. Signiﬁcantly refurbished in April 2004, it is probably the largest university facility for terahertz research in Europe, and one of the largest in the world. The facility contains eight optical benches that include an impressive array of equipment: ﬁve pumped Ti: sapphire laser systems, a Bruker 66V FTIR spectroscopy system, three continuous ﬂow helium cryostats and one 1.2 K Oxford Instruments 54 Agilent Measurement Journal

Table of Contents Feed for the Digital Edition of Agilent Measurement Journal - Issue 4 - 2008

Agilent Measurement Journal - Issue 4 - 2008 Delivering Confidence through Compliance with Standards Contents Emerging Innovations Trying Early Device Implementations at the IEEE 1588 PlugFest Achieving Greater Confidence in Measurement Accuracy through Consistency in Calibration Services Overcoming the Challenges of RFID Component Testing 3GPP LTE: Introducing Single- Carrier FDMA Ensuring Reliable Operation and Performance in Converged IP Networks Testing Storage Area Networks and Devices at 8.5-Gb/s Fibre Channel Rates Choosing an Appropriate Calibration Method for Vector Network Analysis Making Traceable EVM Measurements with Digital Oscilloscopes Exploring Terahertz Measurement, Imaging and Spectroscopy: The Electromagnetic Spectrum’s Final Frontier Interpreting Quoted Specifications when Selecting Digitizers

Agilent Measurement Journal - Issue 4 - 2008

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