ZGP Optical Parametric Oscillator Research Articles

Efficient long-wave infrared ZGP optical parametric oscillator pumped by a diode-pumped AO Q-switched Ho:YAG laser

We describe an efficient long-wave infrared optical parametric oscillator based on ZnGeP2 crystal pumped by a diode-pumped AO Q-switched Ho:YAG laser in this paper. The wavelength of the laser pulse generated by Ho:YAG laser is 2.09-μm, and the maximum output average power is 25.3 W at repetition rate of 10 kHz. When pumped by such Ho:YAG laser, the maximum average output power of 0.66 W at 9.8 μm is achieved, corresponding to slope efficiency of 5.0% and optical efficiency of 2.6%. Furthermore, the beam quality factor of the long-wave infrared beam is measured to be approximately 1.3. To the authors’ best knowledge, this is the best performance reported for a long-wave infrared ZGP-OPO pumped by a diode-pumped AO Q-switched Ho:YAG laser.

Low-threshold mid-infrared ZGP optical parametric oscillator pumped by wavelength-selectable Tm:YLF laser at 1.93 μm

Low-threshold mid-infrared ZGP optical parametric oscillator pumped by wavelength-selectable Tm:YLF laser at 1.93 μm

Formula omitted] optical parametric oscillator with wide temperature tuning

This paper investigated the output characteristics of ZGP optical parametric oscillator (OPO) with tuning over a wide temperature range. The temperature-dependent Sellmeier equation of the ZGP crystal was obtained, and the temperature-tuned curves of ZGP OPO at different phase matching angles were calculated. For temperatures ranging from 25 °C to 200 °C, a tunable long-wave laser at 7.08–7.50 μm, 7.40–7.95 μm, and 7.79–8.47 μm was obtained when the phase matching angles were 51.3°, 50.95°, and 50.6°, respectively. The total tuning range was 1.39 μm. When the idler wavelength was 8.348 μm, the output energy was 0.520 mJ with a pulse width of 15.5 ns, the corresponding slope efficiency and optical conversion efficiency were 10.22% and 8.15%, respectively. The laser has advantages of a wide tunable range and compact mechanical configuration, extending the tuning method of ZGP OPO, which is important in promoting the development of long-wave lasers with a wide tuning range.

High-power mid-infrared ZGP optical parametric oscillator directly pumped by pulsed Tm:YLF laser at 1908 nm

This paper presents the first demonstration of a mid-infrared optical parametric oscillator (MIR OPO) based on ZGP crystal which was directly pumped by an acousto-optical Q-switched Tm:YLF laser at 1.908 μm. Profited from the improved quality of ZGP crystal with low absorption coefficient (<0.04 cm−1) and high laser-induced damage threshold (>3 J/cm2) at 1.908 μm, output power of 17.8 W for both the 3.53 μm signal and 4.15 μm idler lasers was achieved when the double-pump-pass, doubly-resonated ZGP OPO was pumped at 28.6 W. To the best of our knowledge, this is the highest output power and efficiency for any kind of Tm-laser directly-pumped OPOs.

5.4 W, 9.4 ns Pulse Width, Long-Wave Infrared ZGP OPO Pumped by Ho:YAG MOPA System

We demonstrated a narrow pulse-width long-wave infrared ZnGeP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (ZGP) optical parametric oscillator (OPO) pumped by a 2.1 μm Ho:YAG master oscillator power-amplifier (MOPA). By short-cavity structure, a minimum pulse width of ~12 ns was achieved at 1kHz, 2kHz and 3kHz in Ho:YAG oscillator. By employing a three-stage amplifier, a maximum average output power of 73.1 W with pulse width of ~17 ns at the pulse repetition frequency of 3 kHz was obtained. Then a ZGP OPO pumped by the Ho:YAG MOPA was demonstrated. The maximum average output powers of 5.48 W at 8.2 μm and 22.4 W at 2.8 μm were obtained, corresponding to the pulse width of <; 10 ns.

Growth and Characterizations of ZnGeP2 Crystal by a Vertical Bridgman Method

Abstract ZnGeP 2 (ZGP) single crystal with size of 24 mm in diameter and 70 mm in length was grown by a modified vertical Bridgman (VB) method in a three-zone furnace. The crystal was annealed in ZnGeP 2 powder at 600 °C for 500 h. X-ray diffraction (XRD), X-ray fluorescence (XRF) and Fourier transform infrared spectrophotometry (FTIR) were employed to characterize its properties. A ZGP optical parametric oscillator (ZGP-OPO) device was fabricated from the annealed sample. Laser experiment was carried out on the device. Tunable mid-infrared laser in the range of 3∼5 μm was realized on the ZGP-OPO pumped by 2.1 μm, 7 kHz laser. All the results indicate that our grown crystal is in good quality and can be used for nonlinear optical applications.

High power Q-switched Ho: YVO4 laser resonantly pumped by a Tm-fiber-laser

In this document, we describe an efficient room temperature Q-switched Ho:YVO4 laser pumped by a 1940 nm Tm-fiber laser. The Q-switched Ho:YVO4 laser with nearly diffraction limited beam quality and a 1940 nm Tm-fiber laser used as a pump source, are being reported for the first time. A maximum average output power of 11.4 W was obtained at 10 kHz, corresponding to a slope efficiency of 41.2% at 2052.4 nm. A minimum pulse width of 19.3 ns was obtained, corresponding to a peak power of 59 kW. The output beam had quality of M2 factor with Mx2 of 1.02 and My2 of 1.03 at a 10 W output level. In addition, a ZGP optical parametric oscillator (OPO) pumped by the Ho:YVO4 laser was first realized. The ZGP OPO generated total combined output power of 1.9 W at signal wavelength and idler wavelength under a pump power of 9.7 W.

High Power Q-Switched Dual-End-Pumped Ho:YAG Laser

We report the high power acousto-optically Q-switched operation of a dual-end-pumped Ho:YAG laser at room temperature. For the Q-swithched mode, a maximum pulse energy of 2.4 mJ and a minimum pulse width of 23 ns at the repetition rate of 10 kHz are achieved, resulting in a peak power of 104.3 kW. The beam quality factor of M2 ∼ 1.5, which is demonstrated by a knife-edge method. In addition, the Ho:YAG laser is employed as a pumping source of ZGP optical parametric oscillator, and its total average output power is 13.2 W at 3.9 μm and 4.4 μm with a slope efficiency of 68.4%.

Tm:YAP激光抽运ZGP晶体光参量振荡器

Tm:YAP激光抽运ZGP晶体光参量振荡器

Mid-infrared optical parametric oscillator based on ZnGeP2 pumped by 2- \mum laser

We present a 3~5 μm optical parametric oscillator (OPO) based on ZGP pumped by KTP OPO 2.1-μm laser. The tuning curves of ZGP OPO are calculated. The x 6 x 18 (mm) ZGP crystal, whose end faces are antireflection coated at 2.1 and 3.7~4.6 μm, is cut as Θ =53.5o, Φ =0o. When the pump power of 2.1-μm polarized laser is 15 W at 8 kHz, 5.7-W output power and 46.6% slope efficiency are obtained with a ZGPtype I phase match. Central wavelengths of the signal and idler lasers are 4.10 and 4.32 μm, respectively. Pulse duration is about 27 ns. Beam quality factor M2 is better than 1.8. The tunability of 3~5 μm can be achieved by changing the angle of the ZGP crystal.

Room temperature efficient continuous wave and Q-switched operation of a Ho:YAP laser

We report the continuous wave and acousto-optically Q-switched operation of a Tm:YLF-pumped Ho:YAP laser at room temperature. Continuous wave output power of 6.8 W at 2118 nm was obtained under the incident pump power of 13.4 W, corresponding to a slope efficiency of 65.6% and a conversion efficiency of 50.7%. For the Q-switched mode, a maximum pulse energy of 1.28 mJ and a minimum pulse width of 31 ns at the repetition rate of 5 kHz were achieved, resulting in a peak power of 41.3 kW. In addition, the Ho:YAP laser was employed as a pumping source of ZGP optical parametric oscillator, the total average output power of which was 3.2 W at 4.08 and 4.41 μm with a slope efficiency of 69.5%, corresponding to the diode-to-mid-IR conversion efficiency of 9.0%.