Short pulse, high peak power, diode pumped, passively Q-switched 946 nm Nd:YAG laser

We report on generation of 946 nm laser pulses of a few nanosecond duration and up to 3.7 kW peak power from a compact diode-pumped passively Q-switched Nd:YAG laser. This power is 2.5 times as much as what previously has been obtained from this type of a laser. The short pulses with the record high peak power may be particularly attractive for laser range finding type applications.     

Passively Q-switched,high peak power Nd:YAG laser pumped by QCW diode laser

A Nd:YAG laser passively Q-switched by a Cr:YAG showed a high single pulse energy of 53.0 mJ and 5.1 MW peak power. The laser was pumped by quasi-continuous-wave diode bars from single side. The Q-switched pulse had optical-to-optical efficiency of 12% and average temporal duration of 10.4 ns when Cr:YAG with initial transmission of 9.0% was used. Intense pumping as well as very low initial transmission of the saturable absorber gave very high peak power.     

Electro-optically Q-switched 946 nm laser of a composite Nd:YAG crystal

A depolarization phenomenon in an electro-optical crystal in a quasi-three-level 946 nm Nd:YAG laser is observed. A compensation of the thermal effects in electro-optical crystals is achieved by employing a quarter-wave plate, with one optical axis parallel to the laser polarization. This technique allows for the production of an electro-optically Q-switched 946 nm Nd:YAG laser at 1 k Hz. A maximum output power of 350 m W at 1 k Hz repetition frequency and 11 ns pulse duration are achieved with an output coupler of 10% transmission under the incident pump power of 11.1 W, corresponding to a peak power of ～32 k W.     

高平均功率调Q准连续Nd:YAG激光器

通过选用低掺杂浓度的Nd:YAG晶体棒、热近非稳腔优化设计、双棒串接热致双折射补偿技术以及双Q开关正交放置结构，在LD抽运功率1116W时，实现调Q准连续全固态Nd:YAG激光器1064nm输出，平均功率达258W，光束质量M²～15.5，重复频率为10kHz，脉冲宽度为64ns，峰值功率达0.4GW，光光转换效率达23.1%. 关键词： Nd:YAG激光器 准连续波 激光二极管抽运 固体激光器     

LD side-pumped 41 W high beam quality acousto-optical Q-switched single-rod Nd:YAG laser

We report a LD side-pumped high beam quality (M _x ² = 1.20 and M _y ² = 1.19) acousto-optic (AO) Q-switched single-rod Nd:YAG laser with a TEM₀₀-mode dynamic stable cavity. At the pump power of 600 W, 41 W TEM₀₀-mode 1064 nm laser was achieved with electro-optical conversion efficiency of 7%. The repetition rate and pulse width were 30 kHz and 102 ns, respectively with pulse energy of 1.4 mJ and peak power of 13 kW. Up to 24 W of 532 nm green laser was generated by external frequency doubling, corresponding to 59% optical conversion efficiency.     

A flashlamp-pumped 946 nm Nd:YAG laser

Generation of 946 nm radiation from a commercially available, flashlamp-pumped Nd:YAG laser was investigated. By suppression of the high-gain 1.064 m transition and with a specially designed cooling system, a stable emission at 946 nm was achieved in the temperature range 300–240 K. At a repetition rate of 10 Hz laser output powers of 100mW and 500 mW were obtained at room temperature and 240 K respectively. The temperature dependence of unsaturated gain, slope efficiency and pumping threshold were determined.S. Dimov is supported by a fellowship from the Alexander von Humboldt Foundation     

High-peak-power,short-pulse-width,LD end-pumped,passively Q-switched Nd:YAG 946 nm laser

High-peak-power, short-pulse-width diode pumped 946 nm Nd:YAG laser in passively Q-switching operation with Cr⁴⁺:YAG is reported. The highest average output power reaches 3.4 W using the Cr⁴⁺:YAG with initial transmissivity T₀=95%. When the T₀=90% Cr⁴⁺:YAG is employed, the maximum peak power of 31.4 kW with a pulse width of 8.3 ns at 946 nm is generated.     

Nd:YAG laser pumped at 946 nm

A Nd:YAG laser crystal was pumped at 946 nm and lased at 1064 nm. This pump-lase format was investigated in order to reduce the quantum defect between the pump and laser photons as compared to other pump schemes of this material. To the best of our knowledge, this is the first realization of this scheme. A room temperature absorption coefficient and linewidth of approximately 0.075 cm(-1) and approximately 1 nm for 1% at. Nd(+3) concentrations were measured for the 946 nm absorption line. Those parameters impose both narrow-bandwidth pumping and a long absorption path. By increasing the laser crystal temperature above room temperature, the absorption cross sections at 946 and 938 nm increase due to enhanced thermal population of the upper energy level of the ground manifold. The possibility of exploiting this phenomenon to enhance the pump absorption is also discussed.     

Comparison of electro-optical and acousto-optical Q-switched,high repetition rate Nd:GdVO<Subscript>4</Subscript> laser

The differences between the performances of electro-optical (EO) and acousto-optical (AO) Q-switched, diode pumped Nd:GdVO₄ laser at high repetition rates were detailed in this paper. The results revealed that EO Q-switch was more favorable to obtain short pulse width and high peak power laser than AO Q-switch under high repetition rate operation. The minimum pulse widths at 100 kHz were 20.2 ns under EO operation and 28.7 ns under AO operation, corresponding to peak powers of 3.1 kW and 2.2 kW, respectively. The corresponding values at 10 kHz were 5.3 ns, 9.0 ns and 77.4 kW, 45.6 kW, respectively.     

30 mJ, TEM00, high repetition rate, mechanically Q-switched Er:YAG laser operating at 2940 nm

The 2940 nm Er:YAG laser Q-switched mechanically by means of a rotating mirror was developed. It generated the output pulses of up to 30 mJ energy, below 300 ns duration and record repetition rate of 25 Hz. The developed laser was effectively used for the investigation of laser beam interaction with selected organic matter simulants.     

Cavity-dumped electro-optical Q-switched Nd:GdVO4 laser with high repetition rate

We reported a cavity-dumped operation of electro-optical Q-switched Nd:GdVO₄ laser at high repetition rates for the first time. A constant 5.5 ns pulse duration was realized. The maximum average output power was 5.1 W at the highest repetition rate of 50 kHz, corresponding to a peak power of 18.5 kW.     

High peak power laser-diode-pumped passively Q-switched Nd:YVO4/Cr4+:YAG laser

In this paper, we report a high peak power passively Q-switched laser-diode-end-pumped Nd:YVO4/Cr4+:YAG laser polarized along the C axis, generating 4.23-W average power and 18-kW peak power (144-μJ pulse power) with 8.0-ns time duration (29.4-kHz repetition rate) at 1064 nm while the pump power is 21.2 W.     

1064 nm Nd:YAG laser intracavity pumped at 946 nm

We present for the first time a Nd:YAG laser emitting at 1064 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 885 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1064 nm intracavity pumped at 946 nm. We achieved an output power of 7.97 W at 1064 nm for an absorbed pump power at 946 nm of 9.55 W, corresponding to an optical efficiency of 83.4%. The beam quality M² quality factor is about 1.1 at the maximum output power.     

Efficient, single frequency, high repetition rate, PPLN OPO pumped by a prelase Q-switched diode-pumped Nd:YAG laser

Single axial mode operation (<200 MHz optical bandwidth) of a high repetition rate periodically poled lithium niobate optical parametric oscillator (OPO) has been obtained at signal wavelengths between 1.46 μm and 1.64 μm. OPO signal slope efficiencies of 35% have been measured for repetition rates of 5–20 kHz. Single mode operation required spectral narrowing of both the pump laser and the OPO. A simple technique of prelase Q-switching was implemented to reduce the optical bandwidth of the cw diode-pumped Nd:YAG pump laser to <1 GHz. A single intracavity étalon was then sufficient to ensure single frequency oscillation of the OPO signal. The OPO output was stable with a smooth spatial profile and an M ² value of 1.3. Received: 29 September 1999 / Published online: 27 January 2000     

电光调Q脉冲串Nd∶YAG激光器研究

设计了一台高能量输出的电光调Q脉冲串Nd∶YAG激光器,可以对脉冲串重复频率、脉冲数目、脉冲间隔进行调节。重复频率1～10Hz,每一个脉冲串含有1～3个脉,其间隔大于200μs可调。采用平凸腔的结构,对一定重频下的热透镜效应进行补偿。典型的实验结果为:当重频为10Hz、脉冲间隔为548μs时,三脉冲最大输出能量608mJ,双脉冲最大能量输出405mJ,单脉冲最大输出能量为200mJ,其中单个脉冲的脉宽约为8ns,发散角为3.4mrad。     

A 980 nm Yb-doped single-mode fiber laser pumped by a 946 nm Q-switched Nd:YAG laser

We demonstrate a 980 nm single-mode Yb-doped fiber laser with a 946 nm Q-switched Nd:YAG laser used as the pump source. The experimental arrangement exploited a 36.5 cm length of fiber and used the output from both ends of the cavity, providing a total average output power of 100 mW with a slope efficiency of 38%. In order to increase the coupling efficiency and the practicability of the fiber laser, another experimental setup with single ended output was studied, producing an average output power of 80 mW from a fiber length of 23.5 cm. The pulse duration is 10 ns at a repetition frequency of 16 kHz. The linewidth of the laser is 4 nm, ranging from 977 to 981 nm.     

角抽运Nd:YAG复合板条946 nm连续运转激光器

报道了一种适合中小功率输出的全固态激光器的角抽运方法, 抽运光从板条激光器中板条晶体的角部入射, 可获得较高的抽运效率和较好的抽运均匀性.采用单角抽运方式, 首次进行了角抽运Nd:YAG复合板条946 nm连续运转激光器的实验研究. 激光腔采用紧凑型平凹直腔结构, 腔长仅为20 mm. 当注入抽运功率为50 W时, 946 nm激光连续输出功率最高达5.29 W, 光光转换效率为10.6%, 斜效率为12%. 整台激光器结构紧凑, 调谐简单, 成本低, 具有广阔的应用前景. 关键词： 角抽运 Nd:YAG晶体 连续波 946 nm激光     

High repetition rate passively Q-switched diode-pumped Nd:YVO4 laser

We demonstrated an efficient and compact, diode-pumped passively Q-switched Nd:YVO₄ laser operation at 1.064 μm wavelength with high repetition rate, using Cr⁴⁺:YAG as saturable absorber, formed with a simple flat–flat resonator. The maximum CW output power of 4.05 W was obtained at the incident pump power of 8 W. For Q-switched operation, the maximum average output power was measured to be 1.4 W with the corresponding repetition rate of 200 kHz, the pulse width of 60 ns when the initial transmission of Cr⁴⁺:YAG crystal was 85%. The shortest pulse width of 12 ns, the largest pulse energy of 36 μJ and the highest peak power of 3 kW were obtained when the Cr⁴⁺:YAG crystal with an initial transmission of 60% was used.     

High-efficiency diode-pumped acousto-optically Q-switched 1123 nm ceramic Nd:YAG laser

A high-efficiency diode-pumped acousto-optically (AO) Q-switched ceramic Nd:YAG (cNd:YAG) laser operating at 1123 nm is demonstrated for the first time. With an incident pump power of 17.11 W and a pulse repetition rate of 30 kHz, an average output power of 5.86 W is obtained. The optical-to-optical conversion efficiency is 34.2% and the slope efficiency is 39.1%.     

High power single wavelength 1338 nm Nd:YAG laser

Through reasonable coating design to suppress the 1064 nm strongest emission line as well as the 1318.8 nm one, a 1338 nm high-power Nd:YAG quasi-continuous wave (QCW) laser pumped with a Kr lamp has been successfully developed. As high as 102 W of average output power at the 1338 nm single wavelength has been obtained with the overall and slope efficiencies of 4.6% and 6.3%, respectively, when the average pump power is 2200 W. Its threshold power is about 400 W.