The research and fabrication of reflecting diffraction grating for submilimeter electomagnatic pulses

• Main Authors: Gung-Shiung Ho, 何恭璿
• Other Authors: Sheng-Fu Horng
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/66716965594436560497

碩士 === 國立清華大學 === 電機工程學系 === 87 === ABSTRCAT The main purpose of this experiment is to fabricate the reflecting diffraction grating, which is suitable for the electromagnetic pulse with frequency bandwidth of THz(1E12). In this paper, gratings with different period were fabricated and their resolving powers were measured. For proving the correctness of the experiment result, a simple approach that deal with the method of Fourier optics was accomplished. The pulsed electromagnetic source of this experiment was generated from the large aperture emitter with gap structure, which was stimulated by femtosecond Ti:sapphire short pulse laser. The frequency bandwidth of this pulsed E-M source is in the order of THz. In order to detect THz pulsed signal, the pump-prob. E-O crystal detection system was set up. For fabricating the reflecting diffraction grating, we used the method of micro lithography and wet etching to form V-grooves on the surface of the Si wafer. For improving the reflectivity, the grating was coated with an AuGe layer. The idea of the simple approach in this paper was basically follow the method of Fourier optics and the calculation program was accomplished on the Mathematica software.