硒化鎵晶體中遠紅外波段的光學性質與應用

Study of Optical Properties and Application of GaSe Crystal in the mid-and far-infrared

陳晉瑋(Ching-Wei Chen)

《光學工程》 105期 (2009/04) Pp. 7-13

https://doi.org/10.30011/OE.200904.0002

摘要

本文介紹硒化鎵晶體其高非線性的特質與低吸收係數的特性來結合非線性光學的過程來產生同調的中紅外至遠紅外光源。利用差頻的技術來產生同調的紅外光源輸出，其可調範圍從2.4到28 μm。而237.0 cm^(-1)和213.5 cm^(-1)，兩個紅外波段的吸收聲子模態也和光色散性質相互關聯。並提出利用多級的光整流技術於硒化鎵晶體中產生同調的兆赫輻射光源。此技術可應用於兆赫輻射的光譜調控技術與發展高功率兆赫輻射光源輸出的潛力。硒化鎵晶體並進一步利用來做兆赫輻射光參數放大的研究。本研究中，實驗上證實了兆赫輻射的放大現象，初步結果顯示中心頻率於1 THz的兆赫輻射經過此光參數放大器後有2.7倍的功率增益。

關鍵字

硒化鎵晶體 ； 差頻 ； 多級光整流 ； 光參數放大

並列摘要

This study demonstrates the coherent light generation by means of the nonlinear optical processes associated with the GaSe crystal, which possesses the promising characteristics including high nonlinearity and low absorption properties. This promising material is applied to the generation of coherent infrared radiation widely tunable from 2.4 to 28 μm through difference-frequency generation. The infrared-active modes of E-GaSe crystal at 237.0 cm^(-1) and 213.5 cm^(-1) were found to be responsible for the observed optical dispersion and infrared absorption edge. We propose and experimentally demonstrate the generation of single-cycle terahertz radiation with multiple-stage optical rectification in GaSe crystals. This technique can be further used to synthesize a desired spectral profile of output coherent THz radiation and also useful for generating high amplitude single-cycle terahertz pulses. Furthermore, GaSe crystal is a promising nonlinear optical medium to perform the generation of intense THz radiation. Herein, we report the experimental demonstration of terahertz wave amplification in GaSe crystal. Terahertz power amplification factor of about 2.7 times is preliminarily performed under the phase matching condition around 1 THz.

並列關鍵字

GaSe crystal ； Difference-Frequency Generation ； Multiple-stage optical rectification ； Optical Parametric Amplification