waves & beams

Jagadishwar R. Sirigiri
Research Scientist

NW16-184, 167 Albany Street

Cambridge, MA 02139, USA

Phone: (617) 253-8619

Fax:     (617) 253-6078

e-mail: jags@mit.edu

Education

• M.S, and Ph.D., Electrical Engineering & Computer Science, Massachusetts Institute of Technology

• B. Tech., Electronics Engg., Institute of Technology, Banaras Hindu University

Research Interests

My research interests focus on the generation, amplification and transmission of electromagnetic radiation from microwave to Terahertz frequencies. We conduct research on novel vacuum electron device based sources and amplifiers employing different concepts of beam wave interaction such as Cyclotron Resonance Masers, Cherenkov masers etc. We are also investigating new electromagnetic structures such as Photonic Band Gap (PBG) and Quasioptical structures for confinement and transmission of radiation. Various high power sources and amplifiers with unique mode stability and power handling capability have been demonstrated with such novel interaction structures. We also work on modeling of electron beam sources with state-of-the-art 3D codes.

Sources and Amplifiers

Generation and amplification of high power radiation from microwaves to Terahertz frequencies using vacuum electron devices such as cyclotron resonance masers

Gyrotrons

• Megawatt Class Gyrotron Oscillators
  Gyrotron oscillators are capable of generating over 1 MW of power at frequencies in the 100-170 GHz over long pulses of up to 1 minute. They are the workhorses for electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) in magnetic confinement fusion experiments.
  • 1.5 MW, 110 GHz Gyrotron Oscillator
• Novel High Frequency Gyrotron Oscillators
  Low power (10-100 W) and high frequency (100-500 GHz) gyrotron oscillators are being used in Nuclear Magnetic Resonance (NMR) spectroscopy. The radiation from gyrotrons is used to spin polarize biological samples in Dynamic Nuclear Polarization (DNP) Experiments in NMR spectroscopy. We have built gyrotrons at 140 GHz, 250 GHz and 460 GHz in the 10-100W power level for use in NMR spectroscopy. Our research is focused on building novel overmoded yet mode-selective resonators for stable operation of gyrotrons at up to THz frequencies with innovative concepts such as quasioptical and photonic band gap (PBG) structures.
  • Quasioptical Gyrotron
  • Photonic Band Gap Gyrotron
  • 460 GHz Second Harmonic Gyrotron
• Gyrotron Amplifiers
  Gyrotron amplifiers are emerging as the only option for high power amplification in the millimeter wave band especially at frequencies in the W-band (94 GHz) and above. We have demonstrated gyrotron amplifiers at frequency of 140 GHz and are investigating novel interaction structures at higher frequencies.
  • 100 kW, 140 GHz Quasioptical Gyrotron Amplifier
  • 500 W, 140 GHz Gyrotron Amplifier for DNP

Slow Wave Devices

We are investigating novel concepts to build high power slow wave devices such as traveling wave tubes at W-band (94 GHz) and up to THz frequencies. Areas of research include multiple beam devices, overmoded interaction circuits such as PBG structures and other mode selective structures.

Novel Electromagnetic Structures

• Photonic Band Gap Structures
  Novel PBG structures and their applications in confinement and transmission of microwaves, millimeter waves and light. We have successfully used PBG structures as interaction circuits in millimeter wave sources and also in particle accelerators.
  • Quasioptical Gyrotron
• Quasioptical Structures
  

  Novel PBG structures and their applications in confinement and transmission of microwaves, millimeter waves and light. We have successfully used PBG structures as interaction circuits in millimeter wave sources and also in particle accelerators.

  • Photonic Band Gap Gyrotron

Selected Publications

Journal Articles

• Observation of Frequency-Locked Coherent Terahertz Smith-Purcell Radiation, S. K. Korbly, A. S. Kesar, J. R. Sirigiri, and R. J. Temkin, Phys. Rev. Lett., vol. 94, pp. 054803, , 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, Accepted for publication in IEEE Transactions on Plasma Science, 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.
• Experimental Investigation of a 140 GHz Coaxial Gyrotron Oscillator, R. Advani, J. P. Hogge, K. E. Kreischer, M. Pedrozzi, M. E. Read, J. R. Sirigiri, and R. J. Temkin, IEEE Trans. Plasma Sci., vol. 29, no. 6. pp. 943-950, December 2001.
• 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.

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.