70-W average-power doubly resonant optical parametric oscillator at 2 μm with single KTP

We have demonstrated a high-power intra-cavity-pumped doubly resonant optical parametric oscillator (OPO) at 2 μm with single-type II phase-matched KTP. A linearly polarized Q-switched solid-state Nd:YAG laser was used as the intra-cavity pump source, of which the output power and beam quality were improved by cascading two laser rods for compensating the thermal birefringence as well as by placing double acoustic-optical Q-switches orthogonally, and the output power of the doubly resonant OPO was studied versus the temperature of KTP and the repetition rate of the Q-switch. The output power was insensitive to the temperature of KTP in a wide range, and 70-W average power was obtained at 2 μm with the repetition rate of 5 kHz. The stability of the OPO laser was measured to be <3.5 % root mean square at the output power of 70 W for 400 s.

[1]  P B Phua,et al.  120-W continuous-wave diode-pumped Tm:YAG laser. , 2000, Optics letters.

[2]  Y. Bo,et al.  A 200 W diode-side-pumped CW 2 μm Tm:YAG laser with water cooling at 8°C , 2011 .

[3]  武德勇 Wu Deyong,et al.  Intracavity Optical Parametric Oscillator High-Repetition-Rate 2 μm Laser with 46 W Output Power , 2009 .

[4]  H. Hara,et al.  Laser-diode end-pumped Tm(3+):YAG eye-safe laser. , 1996, Applied optics.

[5]  Jirong Yu,et al.  Precise wavelength control of a single-frequency pulsed Ho:Tm:YLF laser. , 2002, Applied optics.

[6]  H. Injeyan,et al.  High power optical parametric oscillator source , 2000, 2000 IEEE Aerospace Conference. Proceedings (Cat. No.00TH8484).

[7]  P B Phua,et al.  Coupled tandem optical parametric oscillator (OPO): an OPO within an OPO. , 1998, Optics letters.

[8]  Chao Zhang,et al.  High-power diode-side-pumped rod Tm:YAG laser at 2.07 μm. , 2013, Applied optics.

[9]  M. Schellhorn.  High-energy, in-band pumped Q-switched Ho(3+):LuLiF(4) 2 microm laser. , 2010, Optics letters.

[10]  P B Phua,et al.  High-efficiency mid-infrared ZnGeP2 optical parametric oscillator in a multimode-pumped tandem optical parametric oscillator. , 1999, Applied optics.

[11]  Baoquan Yao,et al.  High-power, high-quality ZGP OPO pumped by a Tm,Ho:GdVO4 laser , 2010 .

[12]  T. -J. Wang,et al.  3–5 μm AgGaS2 optical parametric oscillator with prism cavity , 2009 .

[13]  Peng Wan,et al.  High pulse energy 2 µm femtosecond fiber laser. , 2013, Optics express.

[14]  P B Phua,et al.  Compact 21-W 2-mum intracavity optical parametric oscillator. , 2000, Optics letters.