Arrayed silicon prism coupler for a terahertz-wave parametric oscillator

被引：0

作者：

机构：

[1] Kawase, Kodo

[2] Shikata, Jun-Ichi

[3] Minamide, Hiroaki

[4] Imai, Kazuhiro

[5] 1,Ito, Hiromasa

来源：

Kawase, K. (kodo@postman.riken.go.jp) | 2001年 / Optical Society of America (OSA)卷 / 40期

关键词：

Crystals - Lithium niobate - Neodymium lasers - Parametric oscillators - Prisms - Q switched lasers - Silicon;

D O I：

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摘要：

Using room-temperature parametric oscillation of a LiNbO3crystal pumped by a Q-switched Nd:YAG laser with a simple configuration, we have realized a widely tunable coherent terahertz- (THz-) wave source in the range between 1 and 3 THz. Inasmuch as the THz wave is affected by total internal reflection at the crystal edge, we used a Si prism coupler to couple out the THz wave. We introduce an arrayed Si-prism coupler that increases the efficiency and decreases the diffraction angle. By use of the arrayed-prism coupler, there is a sixfold increase in coupling efficiency and a 40% decrease in the far-field beam diameter, compared with the use of a single-prism coupler. We discuss the negative effect of the free carriers at the Si-prism surface that is excited by the scattered pump beam, and the positive effect of cavity rotation on the unidirectional radiation of the THz wave from a Si prism. © 2001 Optical Society of America.

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