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D.Li *, K. Imasaki
Institute for Laser Technology, Osaka 565-0871, Japan
X. Gao, J. Hou, Z.Yang
University of Electronic and Science Technology, Chengdu 610054, China Gun-Sik Park
Seoul National University, Seoul 151-747, Korea
* Email: dazhi_li@hotmail.com
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Abstract: It is known that a grating plays a vital role in the development of a terahertz Smith-Purcell device. The transverse diffusion of optical mode in a general grating is regarded to weaken the beam-wave interaction. In this paper, a sidewall grating for the Smith-Purcell device is proposed. The optical beam can be confined between the side walls to avoid transverse diffusion, so it is possible to enhance the coupling of the optical mode with the electron beam. With the help of three-dimensional particle-in-cell simulations, it has been shown that, comparing with the general grating, the usage of a sidewall grating improves the growth rate and dramatically shortens the time for the device to reach saturation. It is also found that the sidewall grating holds the potential to reduce the start current for the operation of a Smith-Purcell device. We also simulated an ongoing experiment, and predicted the radiation characteristics and the current threshold for the device to start oscillation. This is not only an improvement of grating, but also helpful for further understanding the transverse effect of the grating optical mode.
Keywords: terahertz radiation, sidewall grating, Smith-Purcell radiation, three-dimensional simulation
Received: 2008-09-25
Published: 2008-12-22
Acknowledgments: We thank Charlie Brau and Heather Andrews for their helpful discussions. This work is supported by KAKENHI (20656014).
Cite this article:
D. Li, K. Imasaki, X. Gao, J. Hou, Z. Yang. Improvement of Grating for Smith-Purcell Device[J]. International Journal of Terahertz Science and Technology, 2008, Vol.1, No.4: 221-229. DOI:10.11906/TST.221-229.2008.12.18
URL: http://www.tstnetwork.org/10.11906/TST.221-229.2008.12.18
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