Yongchang Zhang

LD End-Pumped c-Cut Nd:YVO(4)/KTP Self-Raman Laser at 560 nm

Intra-cavity sum frequency generation (SFG) of c-cut Nd:YVO4 self-Raman laser was investigated for the first time. A 4 × 4 × 10 mm3 KTP crystal with a type-II phase-matching cutting angle (θ = 83.4°, φ = 0°) was used for SFG between the fundamental light at 1066 nm and first-Stokes light at 1178 nm. The laser system with different curvature radii of output couplers and different pulse repetition frequencies were investigated. At a pump power of 14 W and pulse repetition frequency of 20 kHz, the average output power of yellow-green laser at 560 nm up to 840 mW was achieved, corresponding to a slope efficiency of 7.6% and a conversion efficiency of 6% with respect to diode pump power.

Efficient 1.7 μm light source based on KTA-OPO derived by Nd:YVO 4 self-Raman laser

An intra-cavity optical parametric oscillator (OPO) emitting at 1.7xa0μm derived by Nd:YVO4 self-Raman laser is demonstrated in this Letter, with a KTiOAsO4 (KTA) crystal used as nonlinear optical crystal. A laser diode end-pumped acousto-optic Q-switched Nd:YVO4 self-Raman laser at 1176xa0nm was employed as the pump source. At an incident pump power of 12.1xa0W and a pulse repetition frequency of 60xa0kHz, average output power up to 1.2xa0W signal light at 1742xa0nm was obtained, with diode-to-signal conversion efficiency of 10%. The pulse width was about 11xa0ns and spectral line width was less than 0.5xa0nm for the signal light. The results show that compact intra-cavity KTA-OPO derived by Nd:YVO4 self-Raman laser is an efficient method for 1.7xa0μm waveband laser generation, with potential applications in biological imaging, laser therapy, special materials processing, etc.

Highly efficient CW operation of a diode pumped Nd:Y 2 O 3 ceramic laser

High efficiency continuous-wave laser operation of an in-house made Nd:Y2O3 ceramic was demonstrated. The Nd:Y2O3 laser ceramic was fabricated by vacuum sintering plus the hot isostatic pressing process, whose in-line transmittance reaches 81.6% at the wavelength of 1000 nm. The 1.08 and 1.36 µm CW laser oscillation of an uncoated ceramic sample was experimentally investigated. Both achieved the highest slope efficiency and output power so far reported for the Nd:Y2O3 ceramic lasers. For the operation of 4F3/2-4I11/2 transitions, simultaneous oscillations at 1074.6 nm and 1078.8 nm were observed. At an absorbed pump power of 7.0 W, a maximum output power of 3.01 W was obtained with a slope efficiency of 49.6%. For the laser operation of 4F3/2-4I13/2 transitions, a 1.68 W single wavelength at 1357.7 nm with the slope efficiency of 29.3% was achieved at the absorbed pump power of 6.7 W.

Mid-infrared tunable intracavity singly resonant optical parametric oscillator based on Mgo : PPLN

In this paper, we demonstrated a continuous-wave intracavity singly resonant optical parametric oscillator based on periodically poled MgO:LiNbO3 (MgO:PPLN) pumped by a diode-pumped Nd:YVO4 laser at 1064u2009nm. The singly resonant optical parametric oscillator only outputs the idler light as its cavity high reflectivity was coated at the signal light. When the temperature was controlled at 120°C and the grating period set at 30.5u2009μm for the MgO:PPLN, a maximum idler output power of 1.27u2009W and central wavelength at 3251u2009nm were obtained under an incident diode pump power of 12.4u2009W, corresponding to the conversion efficiency of 10.2%. By changing the temperature and the grating period of MgO:PPLN crystal, widely tunable mid-infrared spectra from 2.95 to 4.16u2009μm were achieved.

1.96-μm Tm:YAG Ceramic Laser

We have demonstrated an efficient diode-end-pumped continuous-wave Tm:YAG ceramic laser at 1962 nm using a compact two-mirror cavity. The laser oscillation at 1962 nm was realized by increasing the cavity loss at 2016 nm to limit oscillation with the strongest laser gain. For comparison, two different output couplers were used to build single wavelength lasers operating at 1962 and 2016 nm. A laser output power of 2.06 W at 1962 nm was achieved for an absorbed pump power of 6.59 W with the laser ceramic temperature maintained at 15xa0°C. The corresponding slope efficiency and conversion efficiency were calculated to be 37.8% and 31.3%, respectively. In contrast, the maximum output power at 2016 nm was approximately 3.47 W under the same conditions. The 1962 nm laser has potential application in the analysis of CO2 and HBr molecular gases.