We report experimental results on an efficient singly resonant optical parametric oscillator (OPO) based on periodically poled MgO-doped LiNbO3. The OPO was pumped by a diode-pumped passively Q-switched Nd:GdVO4 laser, which could produce 3-ns laser pulses with a repetition rate of 5 kHz. By changing the crystal temperature and grating periods, the OPO generated signal and idler output in the ranges of 1.41 to 1.78 µm and 2.7 to 4.3 µm, respectively. The maximum output power at the signal wavelength of 1.55 µm was 35.4 mW with 120-mW pump power. The possibility of using the OPO for trace gas detection was demonstrated through measuring the absorption spectra of methane.
Support vector machine (SVM), is proposed to enhance the measurement accuracy of a temperature-tuning optical parametric oscillator (OPO) gas sensing system. The experimental results demonstrate that the minimum detecting concentration after the use of SVM decreases by more than 8 times.
We report on the use of the temperature-tuned optical parametric oscillator for trace gas detection. A synchronization trace gas detection system was designed and demonstrated, in which the measuring errors caused by the instability of the OPO could be greatly reduced. The trace gas detection system was based on a periodically poled MgO-doped LiNbO3 optical parametric oscillator (OPO) which was pumped by a diode-pumped passively Q-switched Nd:GdVO4 laser. The OPO could produce wavelength-tunable signal output through changing the crystal temperature and the grating periods. The usefulness of the trace gas detection system for spectroscopy was demonstrated by directly measuring the photon absorption spectrum of the methane and acetylene gas cells.
We report on the experimental studies of a diode-end-pumped CW Nd:GdVO<sub>4</sub> laser. CW output power of 19.8 W at 1064 nm and a slope efficiency of 58.5% were obtained under the pump power of 39.5 W. The beam quality M<sup>2</sup> at maximum output power was measured to be around 2.62. The thermal focal length in Nd:GdVO<sub>4</sub> crystal under the pump power from 22 W to 40.6 W was measured.
In this report, polycrystalline Yb:Y 2O3 ceramic laser has been demonstrated for the first time. With a pump power of 11 W at 937 nm, 0.75 W cw laser output at 1078 nm was obtained. The laser had a threshold of 4.7 W and a slope efficiency of 12.6% when an output coupler of R = 98% was used.