Peter H. Siegel
Faculty Associate: Engineering and Applied Science
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Background and Philosophy: Dr. Siegel’s research team specializes in the invention, development and delivery of a wide range of specialized sensor and source devices, components, and instruments spanning the frequency range between 100 and 10,000 GHz which includes the millimeter, submillimeter and far infrared wavelength regimes: the terahertz bands. Emphasis is placed on a cross disciplinary approach which brings together a diverse range of backgrounds and skills that can be directly applied towards progress in bridging the electronic and optical regimes, one of the last remaining technology gaps in the electromagnetic spectrum. Students and staff working with Dr. Siegel include electrical engineers, physicists, biologists and chemists from a wide range of backgrounds and countries. Research work is conducted both at Caltech and at the nearby Jet Propulsion Laboratory, where the emphasis is on Earth, space science and planetary applications of THz technology.
Over the past 24 years Dr. Siegel and his Submillimeter Wave Advanced Technology team at JPL and Caltech have developed and delivered critical sensor hardware for four space flight missions: NASA’s Upper Atmospheric Research Satellite Microwave Limb Sounder, the first instrument to directly measure the anti-correlation between chlorine monoxide build up and ozone depletion on a global scale; NASA’s Earth Observing System Aura Microwave Limb Sounder currently measuring a wide range of stratospheric molecular species involved in ozone depletion, global water distribution, climate change and pollution monitoring across the Earth; European Space Agency’s Microwave Instrument on the Rosetta Orbiter (MIRO), scheduled to rendezvous with comet Churyumov-Gerasimenko in 2014 and measure nuclear temperature and out gassing rates of carbon monoxide, water, ammonia and methanol; and most recently the Heterodyne Instrument for the Far Infrared (HIFI) on the European Space Agency’s Herschel Space Telescope, an ambitious astrophysics mission to record thousands of molecular signatures between 300 and 1900 GHz in and around star forming regions and in external galaxies, as a means of understanding the composition and evolution of the universe. Future mission opportunities include a Discovery class instrument for Venutian cloud measurements, Vesper; a Mars orbiter searching for volcanic emission and life signatures, Marvel/SIGNAL (Submillimeter Investigation of Geothermal Networks and Life); and a Europa orbiter previewing a new technique, Terahertz Radar Absorption Chemistry Experiment (TRACE) being pioneered in the SWAT group, to detect signatures from chemicals sputtered off the Europan surface by the high intensity radiation environment around Jupiter. Third generation Earth science and several new astrophysics missions are also in the near and long term planning and proposal phases.
In addition to Earth, planetary and space science, Dr. Siegel is interested in terrestrial applications of terahertz imaging and spectroscopy and has been actively pursuing several related initiatives in the health and biological sciences at Caltech as well as defense and security applications at both Caltech and JPL. The very first National Institute of Health program in the terahertz field, granted to Dr. Siegel in 2002, had the goal of developing high signal-to-noise imaging and spectroscopy instruments for disease diagnostics. A second THz NIH program to develop low loss terahertz waveguide for endoscopy applications has also been completed. A consortium proposal with Stanford University School of Medicine and ZOmega Inc. to apply this newly established terahertz frequency and time domain instrumentation to skin cancer, in the first US health science application of terahertz in a clinical environment is currently pending. Additional work has also just begun on the thermal and non- thermal effects of millimeter and submillimeter-wave radiation on cellular systems. This work is being undertaken in conjunction with the Caltech biology division and a neurophysiologist, Dr. Victor Pikov, at the Huntington Medical Research Institute. Significant expansion of the biological science work at Caltech is planned for 2012/13 through US NIH, NSF, DoD and a European HFSP proposal with Italy and Korea. Emphasis is being placed on affecting and monitoring cell processes under high frequency, low power, RF exposure. A major goal is to use millimeter waves to stimulate cell membrane depolarization and the formation of nanopores thereby allowing direct, non-contact control of chemical transport. Initial results have now provided the first definitive measurements of significant change in membrane permeability and action potential firing rates on ex vivo cortical neurons from rat pups and neural ganglia in the medicinal leech. In addition, a partnership is planned with UC Berkeley Professor Richard Saykally to use existing and new THz spectroscopy instrumentation for the examination of large molecular count water clusters.
After successful responses to several recent research calls, Dr. Siegel and his group have begun applying submillimeter wave imaging to security and defense. In this application, radar techniques are being applied in the submillimeter wave frequency regime for the very first time. A new class of phenomenology and instrumentation is now emerging that shows great promise for undergarment and threat detection imaging. This application is expected to expand dramatically over the next few years with strong involvement from both JPL and Caltech.
Finally, Dr. Siegel and his research team are dedicated to the long term development of novel devices and components that can push terahertz instruments into mainstream applications. This includes in-house design and fabrication of THz superconductor and semiconductor devices, new single-photon detectors, carbon nanotube based electron tube sources (high efficiency cathodes) and detectors (CNT Schottky diodes), planar array antennas and monolithic GaAs circuits as well as similar programs involving collaborations with research groups and commercial enterprises around the world.
THz Imaging for Biomedical Applications (Caltech): This research was funded under several prior NIH and internal grants and involves the application of terahertz imaging and spectroscopy techniques to problems in the biomedical sciences. Specifically Dr. Siegel has been developing and utilizing the RF instrumentation that was pioneered under his former NASA programs for disease diagnosis, measurements of tissue properties, enhancing contrast through common biomedical staining techniques, and most recently to the impact of THz radiation on cellular processes.
THz Effects on Cellular Systems (Caltech/HMRI): This new program attempts to quantitatively examine THz (and millimeter wave) radiation impact on cells and cellular processes. It blends biological, optical and RF instrumentation in a novel way to examine RF dosimetry effects while directly monitoring cell lines and will establish one of the first IR Raman/optical/RF test instruments for microscopic evaluation of thermal and chemical processes at the cellular level. A proposal to continue the work is currently awaiting review at the NIH with collaborator Dr. Victor Pikov, a neurophysiologist at the Huntington Medical Research Institutes.
THz Detection of BC & SC Carcinoma (Caltech/Stanford/RPI): THz imaging has already been proven to be effective in delineating tumor margins on areas of the body that are near the surface, i.e. skin or surgically exposed regions. Our efforts involve establishing real time video imaging instruments in the THz bands (using pulsed time domain techniques developed at ZOmega – Renssalaer Polytechnic Institute) and then applying these in an actual clinical environment – Stanford University Medical Center – to establish efficacy for diagnosing, and perhaps someday thermally treating, skin lesions, specifically basal and squamous cell carcinoma. This work has been proposed through NIH but has not yet received funding. The work has been ongoing at a low level in the hopes of acquiring sufficient data to bolster future proposal efforts. Collaborators include Professor Scott Fraser at Caltech and Dr. David Peng, a clinical dermatologist at Stanford Medical Center and Tom Tongue, CEO of ZOmega Inc.
THz Radar Imaging (Caltech/JPL): Using our NASA developed source and sensor technologies we have started the first work on THz FMCW radar. In this very exciting program we have designed, fabricating and begun testing a 670 GHz FMCW radar imager that can mechanically scan and 3D reconstruct (using radar ranging) objects between 1 and 25 meters distance with cm resolution in all three dimensions. Since THz waves can pass through many dielectrics, the system is being applied to undergarment threat detection. However significant phenomenologic breakthroughs have already been established through the use of this established technique in this new frequency range. The ultimate goal of the program is to demonstrate near video rate imaging over a modest angular scene scale. The work is being supported by the DoD and most of the instrumentation resides at JPL. Program participants include a number of JPL SWAT team members, particularly Dr. Ken Cooper, Dr. Goutam Chattopadhyay and Mr. Robert Dengler. Other contributors are Dr. Nuria Llombart and Dr. Tomas Bryllert, as well as JPL’s Dr. Imran Mehdi, Dr. Choonsup Lee, Dr. Anders Skalare and Dr. Erich Schlecht.
THz Radar Imaging using Integrated Planar Arrays (Caltech/JPL): Although not yet funded, this program is intended as a follow-on to the radar imaging program already described. In this approach, novel planar array architectures combined with GaAs MMIC transceiver circuitry are envisioned for the realization of phased array transceivers at 300 GHz. Applications go well beyond the security screening field and spill over into multipixel spectrometers for both the space science and biomedical areas. A low level design effort is ongoing as a precursor to future proposal opportunities that may materialize in the coming year. Primary collaborators include the JPL SWAT group, Teledyne - Thousand Oaks and former Caltech postdoctoral Dr. Nuria Llombart (currently at Complutense University of Madrid )
Source and Sensor Development: This ongoing set of tasks has been the core of the JPL SWAT team work for more than 15 years and represents the major thrust of the Earth, planetary and space science applications. A continually evolving set of technical goals and spectroscopic techniques and applications derive from the devices and components that are being developed. These span the frequency range from 100 GHz to 5 THz and include two and three terminal semiconductor devices, passive waveguide and quasi optical components, novel planar and planar array antennas, superconducting detectors, carbon nanotube based sensors and sources, many varieties of upconverter and downconverter circuits and any components that might be critical for achieving a particular instrument goal. The work spans both development and actual delivered flight components, subsystems and instruments. The team works with scientists, engineers and flight systems people to propose, plan, and implement NASA missions and collaborates with space agencies and institutions world wide. The team has so far delivered flight hardware for four major programs including two Earth science, one planetary and one space science mission. Major participants include JPL’s Dr. Imran Mehdi, Dr. Lorene Samoska, Dr. Jonathon Kawamura, Dr. Erich Schlecht, Dr. Goutam Chattopadhyay, Dr. Anders Skalare, Dr. Ken Cooper, Dr. Boris Karasik, Dr. Hamid Javadi, Dr. Andy Fung, Dr. Harish Manohara, Dr. Frank Maiwald, Dr. John Gill, Dr. Choonsup Lee, Dr. Faouzi Boussaha, Dr. Cecile Jung, Dr. Bertrand Thomas, Mr. Robert Dengler, Mr. Robert Lin, Mr. Alex Peralta, Mr. David Pukala, and Mr. Seth Sin.
Dr. Siegel's team operates nine separate laboratory facilities at JPL containing a large range of terahertz test and measurement equipment. These include microwave, millimeter, submillimeter and optical components and instruments as well as sophisticated microassembly and inspection equipment and some biologic processing equipment. He also is a supervisor of, and has access to the JPL Micro Device Laboratory (MDL) with a 100,000+ square foot clean room housing direct write e-beam, wet and dry etching, sputter and thermal coating, bonding, MBE and a wide variety of chemical and optical processing equipment. At Caltech Dr. Siegel is working in the millimeter wave MMIC lab in Moore where he has epi-fluorescence inverted and upright microscopes, an incubator, and an RF exposure system for studying cell level responses and processes and access to the laboratory and animal facilities in the Caltech Beckman Institute where he works with the staff under the direction of Professor Scott Fraser, Anna Rosen Professor of Biology and Director of the Biological Imaging Center.
ChemMatters, “Peter Siegel: Studying the Energy of the Universe,” an interview article for the American Chemical Society, Sept. 2002, pp. 6-7
NIH e-Advances, “Retooling a Research Career - From Engineering to Biology and Back,” an e-interview for the National Institute of Health, June 2006.
BioOptics World, "Can Neurons Sense Millimeter Waves, a feature article by Barbara Goode, February 2010
Institution of Engineering and Technology, interview and feature supplement article, Electronics Letters, Interview with Dr. Peter Siegel, Dec. 2010
Co-author of Best Paper of the Decade award, Indium Phosphide and Related Materials Conference, 1998
Keynote Lecture and Highlighted Article for an opening exhibit of the National Electronics Museum: “Sir Jagadis Chunder Bose: Traversing the Interdisciplinary Gap Between Physics and Biology,” November 2008.
125 professional staff and student hires
Supervisor of 1 Doctoral, 1 Masters, 2 Senior theses
PI or co-I on 65+ research programs totaling more than $60M spanning 25 years
1000+ pages of technical reports!
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Last updated May 2, 2012.