Ph.D., Electrical Engg. & Comp. Sci., Massachusetts Institute of Technology, 2002
M. S., Electrical Engg. & Comp. Sci., MIT, 1999
B. Tech., Electronics Engg., Institute of Technology, Banaras Hindu University

Research Interests

My research interests focus on the generation, amplification and transmission of electromagnetic waves from

1.5 GW MS, 110 GHz Gyrotron

microwave to terahertz frequencies and their applications. We conduct research on novel vacuum electron device based sources and amplifiers employing different concepts of beam wave interaction. We are also investigating new electromagnetic structures such as Photonic Band Gap (PBG), Metamaterials, and Quasioptical structures for confinement, manipulations and transmission of terahertz waves.

Gyrotrons

A significant part of research is in the area of fast wave devices such as gyrotrons, gyroklystrons and gyro-TWTs for producing high peak and average power at frequencies in the millimeter and terahertz spectrum. We have demonstrated a 110 GHz, 1.5 MW gyrotron oscillator with total efficiency exceeding 50 % for plasma heating applications. We are interested in the physics of gyrotron interaction and the microwave engineering aspects of the device.

Terahertz Traveling Wave Tubes (TWT)

Scaled down 94 GHz TWT Interaction Structure

We are conducting research on overmoded slow wave devices such as traveling wave tubes that can generate tens of watts of power at frequencies as high as 500 GHz. We are currently developing a 100 W average power TWT at 94 GHz.

Metameterial Based Vacuum Electron Devices

Novel vacuum electron sources using Metamaterials can be miniaturized and fabricated using planar fabrication techniques. We are conducting research in this area to eventually build vacuum electron devices directly on a chip using modern semiconductor fabrication techniques.

Electron Cyclotron Resonance Heating

We work closely with other groups in the application of microwave and terahertz waves in the areas of electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD), plasma diagnostics.

Dynamic Nuclear Polarization for Sensitivity Enhanced NMR

In collaboration with the MIT Francis Bitter Magnet Lab we have conducted pioneering research in the development of instrumentation for sensitivity enhanced Nuclear Magnetic Resonance (NMR) spectroscopy of biological solids using Dynamic Nuclear Polarization (DNP). We have built systems for DNP at 200, 400, 500 and 700 MHz with gyrotrons at 140, 250, 330 and 460 GHz respectively. We are also developing gyrotron amplifiers at 140 GHz and 250 GHz for Electron Paramagnetic Resonance (EPR) and pulsed DNP.

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Current Research Projects

Spectra of Bacteriorhodopsin obtained using a DNP-NMR spectrometer

110 GHz, 1.5 MW Gyrotron Oscillator
We are investigating the physics of high efficiency interaction in gyrotrons at megawatt power level. We have demonstrated 50 % efficiency at 1.5 MW. Our goal is to demonstrate > 60 % efficiency at 1.5 MW power level. Our group reported the first experimental evidence of After Cavity Interaction (ACI) in gyrotrons. We are working on techniques to suppress ACI in gyrotrons. Advanced internal mode converters with smooth mirrors are also being investigated.
330 GHz Tunable Gyrotron for DNP
We are developing a 330 GHz gyrotron with > 1 GHz of tuning for DNP at 500 MHz. The tunable gyrotron will allow the use of a NMR magnet without an expensive sweep coil for performing advanced DNP experiments.
94 GHz TWT Amplifier
We are developing a novel overmoded TWT amplifier at 94 GHz for generating over 100 W of average power with a gain > 40 dB. The successful demonstration of this device will enable the development of amplifiers at frequencies as high as 650 GHz with a few watts of average power in a compact system
250 GHz Gyrotron Amplifier
A 250 GHz gyrotron amplifier is under development for generating up to 1 kW of peak power with a gain of 45 dB. The device will be used for electron paramagnetic resonance (EPR) and pulsed DNP applications.
Effects of HPM
We are studying the effects of high power millimeter wave radiation on electronics and countermeasures for protecting receiver electronics from the harmful effects of HPM.

Recently Completed Projects

Professional Memberships

Member, IEEE
Member, American Physical Society (APS)
Member, Union of Concerned Scientists (UCS)
Member, Sigma Xi

Awards and Honors

Guest Editor, Twelfth Special Issue on High Power Microwave Generation of the IEEE Transactions on Plasma Sciences.
Session Organizer, Fast Wave Devices, IEEE Pulsed Power and Plasma Science Conference, Albuquerque, New Mexico, June 2007.
Invited Lecture, Recent Progress on ECH Technology for ITER, 47th Annual DPP Meeting of American Physical Society, Oct. 2005.
Invited Keynote: Results of a 460 GHz Second Harmonic Gyrotron Oscillator for Sensitivity Enhanced NMR, Joint 29th IRMMW2004 / 12th THz, Sept. 2004.
Invited Keynote, Mode Selective Gyrotron with a Photonic Band Gap Resonator, 26th International Conference on Infrared and Millimeter-Waves (IRMMW 2001), Tolouse, France, Sept. 2001.

Publications

Selected Journal Articles

Cryogenic sample exchange NMR Probe for Magic Angle Spinning Dynamic Nuclear Polarization, A. B. Barnes, M. L. Mak-Jurkauskas, Y. Matsuki, V. S. Bajaj, P. C. A. van der Wel, R. DeRocher, J. Bryant, J. R. Sirigiri, R. J. Temkin, J. Lugtenburg, J. Herzfeld, and R. G. Griffin, vol. 198, no. 2, pp. 261-70, Journal of Magnetic Resonance, June 2009.
Demonstration of a 140-GHz 1-kW Confocal Gyro-Traveling-Wave Amplifier, C. D. Joye, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, vol. 56, no. 5, pp. 818-27, IEEE Trans. on Electron Devices, May 2009.
Simulation of the Bulk and Surface Modes Supported by a Diamond Lattice of Metal Wires, M. A. Shapiro, K. R. Samokhvalova, J. R. Sirigiri, R. J. Temkin, and G. Shevts, vol. 104, no. 10, pp. 103107, Journal of Applied Physics, Nov. 2008.
High-Field Dynamic Nuclear Polarization for Solid and Solution Biological NMR, A. B. Barnes, G. De Paepe, P. C. A.. van der Wel, K. N. Hu, C. G. Joo, V. S. Bajaj, M. L. Mak-Jurkauskas, J. R. Sirigiri, J. Herzfeld, R. J. Temkin and R. G. Griffin, vol. 34, no. 3-4, pp. 237-63, Applied Magnetic Resonance, Aug. 2008.
Dynamic Nuclear Polarization at High Magnetic Fields, T. Maly, G. T. Debelouchina, V. S. Bajaj, K. N. Hu, C. G. Joo, M. L. Mak-Jurkauskas, J. R. Sirigiri, P. C. A. van der Wel, J. Herzfeld, R. J. Temkin and R. G. Griffin, vo. 128, no. 5, pp. 052211, Journal of Chemical Physics, Feb. 2008.
Observation of Large Arrays of Plasma Filaments in Air Breakdown by 1.5-MW 110-GHz Gyrotron Pulses, Y. Hidaka, E. M. Choi, I. Mastovsky, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, vol. 100, no. 3, pp. 035003, Physical Review Letters, Jan 25, 2008.
250 GHz CW Gyrotron Oscillator for Dynamic Nuclear Polarization in Biological Solid State NMR, V. S. Bajaj, M. K. Hornstein, K. E. Kreischer, J. R. Sirigiri, P. P. Woskov, M. L. Mak-Jurkauskas, J. Herzfeld, R. J. Temkin and R. G. Griffin, vol. 189, no. 2, pp. 251-79, Journal of Magnetic Resonance, Dec. 2007.
Experimental Observation of the Effect of Aftercavity Interaction in a Depressed Collector Gyrotron Oscillator, E. M. Choi, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, vol. 14, no. 9, pp. 093302, Physics of Plasmas, Sept. 2007.
Efficiency Enhancement of a 1.5-MW, 110-GHz Gyrotron With a Single-Stage Depressed Collector, E. M. Choi, A. J. Cerfon, I. Mastovsky, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, vol. 52, no. 2, pp. 334-9, Fusion Science and Technology, Aug. 2007.
Spatial Dispersion in Metamaterials With Negative Dielectric Permittivity and its Effect on Surface Waves, M. A. Shapiro, G. Shvets, J. R. Sirigiri, and R. J. Temkin, vol. 31, no. 13 pp. 2051-3, Optics Letters, July 1, 2006.,
Experimental Results For a 1.5 MW, 110 GHz Gyrotron Oscillator With Reduced Mode Competition, E. M. Choi, C. D. Marchewka, I. Mastovsky, J. R. Sirigiri, M. A. Shapiro, and R. J. Temkin, vol. 13, no. 2, pp. 023103, Physics of Plasmas, Feb 2006.
Observation of Frequency-Locked Coherent Terahertz Smith-Purcell Radiation, S. K. Korbly, A. S. Kesar, J. R. Sirigiri, and R. J. Temkin, vol. 94, pp. 054803, Phys. Rev. Lett., Feb. 2005.
Second Harmonic Operation at 460 GHz and Broadband Continuous Frequency Tuning of a Gyrotron Oscillator, M. K. Hornstein, V. S. Bajaj, R. G. Griffin, I. Mastovsky, M. A. Shapiro, , J. R. Sirigiri, and R. J. Temkin, vo. 52, no. 5, pp. 798-807, IEEE Trans. Electron Devices, May. 2005.
High-Power 140-GHz Quasioptical Gyrotron Traveling-Wave Amplifier, J. R. Sirigiri, M. A. Shapiro, and R. J. Temkin, Phys. Rev. Lett., vol. 90, no. 25, pp. 258302(1- 4), June 2003.
Simulation of Photonic Band Gaps in Metal Rod Lattices for Microwave Applications, E. I. Smirnova, C. Chen, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, J. Appl. Phys., vol. 91, no. 3, pp. 960-968, 1 February, 2002.
Photonic-Band-Gap Resonator Gyrotron, J. R. Sirigiri, K. E. Kreischer, J. Machuzak, I. Mastovsky, M. A. Shapiro, and R. J. Temkin Phys. Rev. Lett., vol. 86, no. 24, pp. 5628-2631, June 2001.

full list of publications

Patents

Vacuum Electron Device with Photonic Band Gap Structure and Method of Use Thereof, Chiping Chen, M. A. Shapiro, J. R. Sirigiri, and R. J. Temkin, United States Patent No. US 6,801,107 B2, Oct. 5, 2004. (top)
Photonic band gap structure simulator, C. Chen, M. A. Shapiro, E. I. Smirnova, and R. J. Temkin, J. R. Sirigiri, United States Patent No. US 7,117,13, 10/03/2006

waves & beams

Jagadishwar R. Sirigiri Research Scientist

Education