Continuous-wave laser operation of Yb:LuVO4

We report on the room-temperature spectroscopic properties and continuous-wave laser operation of a new Yb:LuVO4 crystal. The peak absorption cross section for the pi-polarization is 8.42 x 10(-20) cm2 at 985 nm, and the stimulated emission cross section at 1020 nm is 1.03 x 10(-20) cm2. An output power of 0.36 W at 1041 nm was obtained with a slope efficiency of 47% by use of Ti:sapphire laser pumping. With diode pumping the output power reached 1.05 W at the highest available incident pump power of 6.8 W.     

Continuous-wave and passively Q-switched laser performance of a disordered Nd:GYSGG crystal

The performance of continuous wave (CW) and passively Q-switched Nd:GYSGG lasers was investigated for the first time. The CW output powers of 4.2 W with dual wavelength of 1058.4 nm and 1061.5 nm were obtained under the diode pump power of 17 W with slope efficiencies of 26%. By using Cr⁴⁺:YAG wafer as saturable absorber, Q-switching operation was performed and the short pulse with pulse width of 6.6 ns was obtained with the peak power of 9.97 kW.     

Diode-pumped continuous-wave Nd:LuVO4 laser operating at 916 nm

We realized an efficient diode-pumped Nd:LuVO4 continuous-wave (CW) laser operating at 916 nm. Laser experiments with 0.5 at. % Nd-doped Nd:LuVO4 crystals of various lengths and cutting directions were also investigated. The maximum output power of 930 mW was obtained with a slope efficiency of 27.2% and an optical conversion efficiency of 20.8% at the absorbed pump power of 4.5 W. The laser experiment shows that Nd:LuVO4 crystal can be used for an efficient diode-pumped laser system.     

Continuous-wave laser at 440 nm based on frequency-doubled diode-pumped Nd:GdVO(4) crystal

We present for the first time, to the best of our knowledge, a frequency-doubled Nd:GdVO(4) laser operating in a cw on the pure three-level laser line at 880 nm. We obtained 300 mW at 440 nm for 23 W of incident pump power at 808 nm. Moreover, with a 25% output coupler we obtained a cw power of 1.9 W at the fundamental wavelength at 880 nm.     

LD抽运Nd:LuVO4微片激光器性能研究

报道了一类新型的LD端面抽运Nd:LuVO4微片激光器,讨论了在不同掺杂浓度,不同厚度和不同透过率下的激光性质,测定了在不同抽运功率下,微片最佳激光输出功率与LD抽运温度的关系.在2W抽运功率下获得923mW的1064nm激光输出,阈值为48mW,斜效率为52%.对微片制冷后斜效率提高到59%.     

Continuous-wave Nd:KGd(WO4)2 single-longitudinal-mode laser

A continuous-wave Nd:KGd(WO₄)₂ single-longitudinal-mode laser is demonstrated with Fabry-Perot etalons in a simple linear cavity. The thermal lens effect is dramatically lowered by propagating the laser beam along the ‘athermal’ direction inside the laser crystal, which is very beneficial to removing the heat generated in the mode selection process. The maximum single-longitudinal-mode output power obtained is 64.8 mW at incident pump power of 4.7 W, corresponding to an optical conversion efficiency of 1.3% and a slope efficiency of 1.7%.     

Simultaneous mode locking in an acousto-optic Q-switched Nd:LuVO4 laser

Simultaneous mode locking had been obtained in acousto-optic Q-switched Nd:LuVO₄ laser by using a Z-type cavity. Pulses with great average output power and narrow pulse width were observed in our experiment. The modulation depth is nearly 90% and the width of Q-switched envelope is about 70 ns, and both maintained constant with the increase of pump power. The maximum average output power of 1.83 W was obtained when the incident pump power was 6.78 W and the Q-switched envelop repetition frequency was 30 kHz. Also the average pulse width of the mode locking among the Q-switched envelope is estimated to be about 200 ps.     

Continuous-wave laser at 453 nm based on frequency-doubled diode-pumped Nd:ASL crystal

Efficient and compact is generated by intracavity frequency doubling of a diode-pumped Sr_1−x La _{x − y} Nd _y Mg _x Al_{12 − x} O₁₉(Nd:ASL) laser at 906 nm. With 10.3 W of diode pump power and the frequency-doubling crystal LiB₃O₆ (LBO), a maximum output power of 281 mW in the blue spectra] range at 453 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 2.7%; the output power stability over 4 h is better than 3.8%.     

Continuous-wave and actively Q-switched Nd:LSO crystal lasers

With a fiber coupled laser diode array as the pump source, Nd-doped Lu₂SiO₅ (Nd:LSO) crystal lasers at ⁴F_3/2→⁴I_11/2 and ⁴F_3/2→⁴I_13/2 transitions were demonstrated. The active Q-switched dual-wavelength lasers at about 1.08 μm, as well as continuous-wave (CW) and active Q-switched lasers at 1357 nm are reported for the first time, to the best of our knowledge. Considering the small emission cross-sections and long fluorescence lifetime, this material possesses large energy storage ability and excellent Q-switched properties. The special emission wavelength at 1357 nm will have promising applications to be used in many fields, such as THz generation, pumping of Cr³⁺:LiSAF, repumping of strontium optical clock, laser Doppler velocimeter and distributed fiber sensor.     

High-power laser performance of a-cut and c-cut Yb:LuVO4 crystals

We report high-power laser operation that was achieved with a-cut and c-cut Yb:LuVO(4) crystals. Up to 8.3 W of pi-polarized output power was generated from an a-cut, 2 mm uncoated crystal with an optical conversion efficiency of 59%. The highest slope efficiency was 80%. Laser oscillation obtained with c-cut crystal was also linearly polarized, with two orthogonal polarization components along [110] and [(-)110] directions. The highest output power achieved was 4.5 W, with an optical conversion efficiency of 33% and a slope efficiency of 40%.     

Passively mode-locked Nd:LuVO(4) laser with a GaAs wafer

We report on the passive mode locking of a diode-pumped Nd:LuVO(4) laser with a GaAs wafer as output coupler. Using the interference modulation effect of the GaAs wafer, high-power continuous-wave mode locking with a pulse width of about 7.1 ps and an average output power of 3.11 W was achieved. Our result shows that Nd:LuVO(4) could be an excellent gain medium for diode-pumped high-power mode-locked lasers.     

Diode-end-pumped passively mode-locked Nd:LuVO4 laser with a semiconductor saturable-absorber mirror

A diode pumped passively mode-locked Nd:LuVO₄ laser with a semiconductor saturable-absorber mirror (SESAM) is demonstrated. The mode-locked pulses have a pulse duration of about 8.8 ps and a repetition rate of 157 MHz. Under an absorbed pump power of 12 W a maximum output power of 3.71 W is obtained, which gives an optical conversion efficiency of 31%. Our results show that Nd:LuVO₄ is a promising gain medium for the high power mode-locked solid-state lasers.     

用倍频晶体KTP实现Nd：YAG激光锁模的研究

报道用倍频晶体KTP实现Nd:YAG激光锁模的系统研究,给出了该锁模激光器输出脉宽的表达式,并和实验测量值相比较,计算值跟实验结果符合较好.文中还分析了各种参数对该锁模激光输出性能的影响.     

脉冲激光二极管侧面抽运Nd:YAG激光器晶体时变热效应

采用数值计算的方法,对脉冲激光二极管三向侧面抽运固体激光器中,激光晶体的温度场时变分布进行了计算. 分析了三向侧面抽运情况下晶体内光强分布,在此基础上,采用有限元法,以脉冲激光二极管侧面抽运Nd:YAG激光器为例,对单脉冲过程中晶体温度分布及其影响因素进行分析. 结果表明,晶体升温过程受到抽运条件以及散热条件的影响,但是主要受到抽运条件即抽运光强度和光束半径的影响,降温过程受到晶体热物性参数和晶体半径以及散热条件的影响. 当晶体温度达到周期性分布后,由于晶体径向温度梯度的周期性变化,引起通过晶体的平面光波的中心和边缘光线相对光程差也随时间作周期性变化.     

Nd:LuVO_4晶体的拉曼光谱研究

采用不同的几何配置测量了Nd:LuVO4晶体的室温拉曼光谱,根据群论对称性分类计算了该晶体的红外和拉曼活性振动模并与实验结果做了比较,指认了测定的特征谱线。测量并分析了Nd:LuVO4晶体A1g全对称类的高温拉曼光谱,讨论了拉曼频移随温度变化的关系,认为晶体的热膨胀是引起拉曼频移变化的主要原因。     

Continuous-wave high-power multi-pass pumped thin-disc Nd:GdVO4 laser

A thin-disc Nd:GdVO₄ laser in multi-pass pumping scheme was developed. Continuous-wave output power of 13.9 W at 1.06 μm for an absorbed power at 808 nm of 22 W was demonstrated from a 250-μm thick, 0.5-at.% Nd:GdVO₄ in a 4-pass pumping; the slope efficiency in absorbed power was 0.65, or 0.47 in input power. Output performances were also investigated under diode laser pumping at 879 nm, directly into the emitting ⁴F_3/2 level: maximum power of 3.6 W was obtained at 6.2 W of absorbed power with 0.69 slope efficiency. Compared with pumping at 808 nm, into the highly absorbing ⁴F_5/2 level, improvements of laser parameter in absorbed power (increase of slope efficiency, decrease of threshold) were obtained, showing the advantages of the pumping into the emitting level. However, the laser performances expressed vs. the incident power were modest owing to the low absorption efficiency at 879 nm. Thus, increased number of passes of the medium would be necessary in order to match the performances in input power obtained under 808-nm pumping.     

Diode-pumped passively Q-switched mode-locked Nd:LuVO4 laser with a semiconductor saturable absorber mirror

We present a compact passively Q-switched mode-locked Nd:LuVO₄ laser run in a Z-type folded cavity with semiconductor saturable absorber mirror (SESAM). The repetition rates of the passively Q-switched pulse envelope ranges from 22.99 to 141.18 kHz as the pump power increased from 2.372 to 8.960 W. The repetition rates of mode-locked laser pulses in the Q-switched pulse envelope has 111 MHz determined by the cavity length and the mode-locked pulse duration is evaluated to be 257 ps. An average output power of 823.5 mW is achieved at the pump power of 8.96 W, corresponding to an optical conversion efficiency of 9.2%.     

Effect of Nd3+ concentration on CW and pulsed performance of fiber-coupled diode laser pumped Nd:YVO4 laser at 1064 nm

The effect of Nd³⁺ concentration on the CW and Q-switched laser performances at 1064 nm from Nd: YVO₄ has been studied under diode laser pumping in identical laser configuration. The Nd³⁺ concentrations used were 1, 2 and 3 at.% in YVO₄ crystals. Under the CW operations we have compared the thermal lensing effect, slope efficiencies and also the beam quality at the fourth-order degeneracy configuration. Q-switching was done with the help of an acousto-optic modulator and we have compared the pulses obtained from Nd: YVO₄ laser with different doping concentration. It was found that the 1 at.%-doped crystal is the best, offering highest optical-to-optical conversion efficiency (55%), lowest fractional heat load (24%), highest pulse energy (80 μJ) and shortest pulse width (20 ns). It was also found that there was not much difference in performances for 2 and 3 at.%-doped crystals both in CW and Q-switched configurations.     

Continuous-wave dual-wavelength operation of a diode-end-pumped Nd:GGG laser

A diode-end-pumped continuous-wave (CW) simultaneous dual-wavelength laser operation at 1062 and 1331 nm in a single Nd:GGG was demonstrated. A total output power of 1.08 W at the two fundamental wavelengths was achieved at the incident pump power of 18.2 W. The optical-to-optical conversion is up to 5.9% with respect to the incident pump power. To the best of our knowledge, this is first work on CW simultaneous dual-wavelength operation of a diode pumped Nd:GGG laser. The article is published in the original.)     

Continuous-wave and Q-switched laser operation of Nd:Gd0.18Y0.82VO4 mixed crystal

Efficient continuous-wave (cw), passively Q-switched, and actively Q-switched laser operations are demonstrated with a mixed vanadate crystal of Nd:Gd_0.18Y_0.82VO₄ under diode pumping. In a cw operation, an output power of 8.25 W is obtained at a maximum available incident pump power (P_in) of 15 W, with a slope efficiency of 56%. Using a Cr⁴⁺:YAG crystal of initial transmission of 62% as the saturable absorber for Q-switching, an average output power of 3.05 W is generated at pulse repetition frequency (PRF) of 16.7 kHz when the laser is pumped with the same maximum P_in. The pulse energy, pulse duration, and peak power are 183.3 μJ, 6.0 ns, and 30.6 kW, respectively. When actively Q-switched by an acousto-optic modulator, the laser produces an average output power of 5.5 W at PRF of 30 kHz with 16.2 W of pump power incident upon the laser crystal. The pulse energy, duration, and peak power are measured to be 183 μJ, 10.5 ns, and 17.5 kW, respectively.