High-Repetition-Rate Terahertz Generation in QPM GaAs With a Compact Efficient 2- \mu \text KTP OPO

• Published in: IEEE photonics technology letters 2016-07, Vol.28 (14), p.1501-1504
• Main Authors: Jialin Mei, Kai Zhong, Maorong Wang, Pengxiang Liu, Degang Xu, Yuye Wang, Wei Shi, Jianquan Yao, Norwood, Robert A., Peyghambarian, Nasser
• Format: Article
• Language: English
• Subjects: Crystals; difference frequency generation (DFG); Gallium arsenide; gallium arsenide (GaAs); Nonlinear optics; optical parametric oscillator (OPO); Optical pumping; Power generation; quasi-phase-matching (QPM); terahertz (THz); Tuning
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2016.2557583

An efficient tunable high-repetition-rate KTiOPO 4 (KTP) optical parametric oscillator (OPO) was deployed as a compact terahertz (THz) source for the first time. The KTP OPO was intracavity pumped by an acousto-optical Q-switched Nd:YVO 4 laser and emitted two tunable wavelengths near degeneracy. The OPO tuning range extended continuously from 2.068 to 2.191 μm with a maximum output power of 3.29 W at 24 kHz, corresponding to an optical-optical conversion efficiency of 20.69%, believed to be among the highest reported. A periodically inverted quasi-phase-matched GaAs crystal was used to generate the THz wave by the difference frequency generation (DFG) method based on a dual-wavelength laser. The maximum output THz power was 0.6 μW at 1.244 THz, and the DFG energy conversion efficiency was 4.32 × 10 -7 . This provides a potential practical palm-top tunable THz sources for portable applications.