Peter H. Siegel

Visiting Associate: Engineering and Applied Science
Senior Scientist: Division of Biology (11 years)
Senior Research Scientist:
Jet Propulsion Laboratory (26 years)
Founder: JPL Submillimeter Wave Advanced Technology (SWAT)

Founder/CEO of THz Global, an international collaborative research consulting team working on a wide variety of THz research and applications

Founder, International Society of
Infrared, Millimeter, and Terahertz Waves

Founding Editor-in-Chief, IEEE Transactions on
Terahertz Science and Technology

B.A. Astronomy, 1976, Colgate University, Hamilton, NY
M.S. Physics, 1978, Columbia University, NY
Ph.D. Electrical Engineering, 1983, Columbia University, NY

Email contact phs AT caltech DOT edu

Research in Terahertz Technology and Applications: Earth and Space Science, Biology, Medicine, Defense and related Civilian opportunities

To view Dr. Siegel's current research and his former research group .

Link to the International Society of Infrared, Millimeter and Terahertz Waves

Link to 39th International Conference on Infrared, Millimeter and Terahertz Waves held at University of Arizona, Tucson from September 14th-19th, 2014.

Link to 33rd International Conference on Infrared, Millimeter and Terahertz Waves held at Caltech from September 15-19, 2008.

Link to IEEE Transactions on Terahertz Science and Technology   THZ Journal
Download flyer for the new journal: THz Journal Flyer
If you wish to be considered for review board membership or to help out with the new journal in any way please email Peter Siegel

Background and Philosophy: Dr. Siegel’s research 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. Dr. Siegel has recently founded a small international consulting company, THz Global, through which he is continuing his THz research work in collaboration with an international team of colleagues with expertise that spans the full range of millimeter and submillimeter wave applications.

Over the past 26 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 2013/14 through US NIH initiatives. 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 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. Additional RF-bio work in 2014 will include millimeter wave monitoring and diagnosis for health applicaitons. Work has already begun with animal experiments at 40 GHz and will continue under a Caltech patent in 2014. .

After successful responses to DoD research calls, Dr. Siegel's group at JPL began applying submillimeter wave imaging to security and defense. In this application, novel radar imaging and ranging techniques were applied in the submillimeter wave frequency regime for the very first time. A new class of phenomenology and instrumentation has now emerged that shows great promise for undergarment and threat detection imaging. This application is expected to expand dramatically over the next few years with growing involvement at JPL.

Finally, Dr. Siegel and his research team have been 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.

Current Research:

Microwave-to-THz Applications in Biology and Biomedicine (Caltech and Huntington Medical Research Institutes): This research was funded under several prior NIH and internal grants and involves the use of microwave, millimeter and submillimeter wave technologies for biological and biomedical applications. 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 and real time monitoring of metabolic processes in the body. Current research is focused on non-invasive glucose monitoring at millimeter wavelengths.

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THz Effects on Cellular Systems (Caltech/HMRI): This 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. The work is conducted with collaborator Dr. Victor Pikov, a neurophysiologist at the Huntington Medical Research Institutes. Additional work on non-invasive millimeter wave monitoring of metabolic processes is awaiting final patent filing and will be pursued through NIH funding in 2015.

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Dr. Siegel is working in the millimeter wave MMIC lab in 362 Moore where he has epi-fluorescence inverted and upright microscopes, an incubator, and an RF exposure system for studying cell level responses and processes. Dr. Siegel also regularly accesses the Huntington Medical Research Institute animal facilities across from Huntington Hopsital, Pasadena, where he works with Dr. Victor Pikov on the millimeter wave bio applications. He frequently consults with and visits with former colleagues and friends from the JPL Submillimeter-Wave Advanced Technology team, which he founded in 1992, and which is currently managed by Dr. Imran Mehdi.

Recent and review papers describing current work: