Widely Tunable High-Repetition-Rate Terahertz Generation Based on an Efficient Doubly Resonant Type-II PPLN OPO

• Main Authors: Jialin Mei, Kai Zhong, Maorong Wang, Yang Liu, Degang Xu, Wei Shi, Yuye Wang, Jianquan Yao, Wanguo Liang
• Format: Article
• Language: English
• Published: IEEE 2016-01-01
• Series: IEEE Photonics Journal
• Subjects: Terahertz; difference frequency generation; optical parametric oscillator; periodically poled LiNbO<sub xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">3</sub> (PPLN)
• Online Access: https://ieeexplore.ieee.org/document/7762105/

We demonstrated a compact, widely tunable, and monochromatic high-repetition-rate terahertz (THz) source based on difference frequency generation in a GaSe crystal. The dual-wavelength pump laser was a doubly resonant near-degenerate type-II periodically poled LiNbO₃ (PPLN) optical parametric oscillator (OPO), intracavity pumped by a 1.064-&#x03BC;m Q-switched Nd:YVO4 laser operating at 25 kHz. The PPLN OPO covered the wavelength range of 2072-2186 nm through temperature tuning with a 55-mm-long nonlinear crystal, and the maximum output power was 3.27 W. The generated THz wave was continuously tunable from 0.24 (1250 &#x03BC;m) to 3.78 THz (79 &#x03BC;m) with the maximum average output power of 1.8 &#x03BC;W at 1.57 THz. Such a compact and portable THz source has great potential for spectroscopy and imaging applications.