二极管泵浦1064nm单频Nd:YVO4激光器的研究

报道了一种用国产激光二极管泵浦的1064nm单频NdYVO4红外激光器的设计.利用布氏片和石英晶体组合构成的双折射滤光片技术,在泵浦功率为800mW时,实现了功率为360mW的1064nm红外单频输出.测量结果表明,偏振比超过了10001,功率稳定性优于0.5%,振幅噪声小于0.1%.     

8.9-W continuous-wave, diode-end-pumped all-solid-state Nd:YVO4 laser operating at 914 nm

A high power laser-diode-array end-pumped 0.2 at % Nd:YVO₄ continuous-wave (CW) laser operating at 914 nm is reported in this letter. The maximum output power of 8.9 W was obtained at the incident pump power of 48.0 W, giving the corresponding optical efficiency of 18.5% and the average slope efficiency of 25.7%. The beam quality factor was measured to be M ² = 2.71 at the output power of 8.0 W by the traveling knife-edge method.     

High power single-frequency continuous-wave Nd:YVO4 master-oscillator power amplifier

We report a highly-efficient, high-power, single-frequency Nd:YVO₄ master-oscillator power-amplifier with near-diffraction-limited output beam quality. A diode-pumped Nd:YVO₄ ring laser incorporating a passive method for suppressing axial-mode-hopping was employed as the master-oscillator, and was amplified by a three-stage diode-end-pumped Nd:YVO₄ amplifier, yielding 79 W of output with an extraction efficiency of 29%. The overall power gain was 15 dB for an input power from the master-oscillator of 2.4 W, and the M² parameter was less than 1.5 at the maximum power. The prospects for a further increase of power and brightness via this approach are considered. PACS 42.55.Xi; 42.60.Da; 42.60.Jf     

Second-Stokes YVO4/Nd:YVO4/YVO4 self-frequency Raman laser

We demonstrated an efficient second-Stokes Raman laser emission at 1313 nm based on self-frequency stimulated Raman scattering from a diode-end-pumped actively Q-switched YVO(4)/Nd:YVO(4)/YVO(4) laser at 1064 nm for the first time, to the authors' knowledge. A double-end diffusion-bonded Nd:YVO(4) composite crystal was adopted for sufficiently improving the thermal lensing effect in the course of self-frequency stimulated Raman scattering operation. With an incident pump power of 14.6 W and a pulse repetition (PRR) of 40 kHz, a maximum average output power of 2.34 W was obtained, corresponding to an optical-to-optical conversion efficiency of 16%. Pulse width and peak power were 1.2 ns and 49 kW, respectively.     

Compact efficient all-solid-state eye-safe laser with self-frequency Raman conversion in a Nd:YVO4 crystal

An efficient compact eye-safe laser at 1525 nm is presented by use of self-frequency Raman conversion in a diode-pumped actively Q-switched Nd:YVO4 1342-nm laser. At an incident pump power of 13.5 W, the self-stimulated Raman laser produces 1.2 W of 1525-nm average output power at a repetition rate of 20 kHz. The corresponding peak power at 1525 nm is generally greater than 10 kW for repetition rates from 5 to 20 kHz.     

Frequency-stabilized Nd:YVO4 thin-disk laser

We have developed a Nd:YVO₄ thin-disk laser at 914 nm with single-frequency operation and active frequency stabilization to a low-finesse reference cavity. The spectral density of laser frequency noise is analysed by means of noise measurements at the error point of the frequency control loop. To address the 3¹S₀→3³P₁ magnesium intercombination line at 457 nm, we use an external frequency doubling stage based on periodically poled KTiOPO₄ for the generation of more than 150-mW output power at 457 nm. Optical beat signal measurements at 457 nm with a frequency-stable dye laser show a short-time line width of the thin-disk laser of less than 100 kHz. PACS 42.55.Xi; 42.60.Lh; 42.62.Fi; 42.65.Ky     

LD连续泵浦Nd:YVO4声光调Q激光器

 利用半导体激光器（LD）连续单端泵浦Nd:YVO₄晶体，实现了声光调Q输出1 064nm的短脉冲。分析并用实验验证了不同透过率输出耦合镜及不同重复频率条件下，输出调Q脉冲能量、脉冲宽度及平均输出功率的规律。在泵浦功率为20.7W，重复频率为50kHz时，获得了最大平均输出功率为5.72W的脉冲，光 光转换效率为28%，斜效率为32.4%；在重复频率为10kHz时，最大单脉冲能量为0.286mJ，脉宽为22ns，峰值功率为13kW。     

LD连续泵浦Nd:YVO4声光调Q激光器

利用半导体激光器（LD）连续单端泵浦Nd:YVO4晶体,实现了声光调Q输出1 064nm的短脉冲。分析并用实验验证了不同透过率输出耦合镜及不同重复频率条件下,输出调Q脉冲能量、脉冲宽度及平均输出功率的规律。在泵浦功率为20.7W,重复频率为50kHz时,获得了最大平均输出功率为5.72W的脉冲,光 光转换效率为28%,斜效率为32.4%;在重复频率为10kHz时,最大单脉冲能量为0.286mJ,脉宽为22ns,峰值功率为13kW。     

LD-pumped Q-switched Nd:YVO4 self-Raman laser

LD-pumped actively Q-switched Nd:YVO₄ self-Raman laser is presented. The maximum average output power of the self-Raman laser at 1173.6 nm was obtained to be 2.21 W at the incident pump power of 18 W and the pulse repetition frequency (PRF) of 30 kHz, with the corresponding optical conversion efficiency of 12.28%.     

高效率多程折叠Nd:YVO4激光放大器

采用具有近共焦、非稳腔特点的多程折叠光路结构,使激光光束多次通过增益介质,实现了高提取效率的激光放大器.实验中在注入22W种子激光的条件下,以43.9%的提取效率得到了63 W的激光输出,斜效率超过52%,激光放大器的输出光束质量从种子激光的M2X=2.08,M2Y=1.92变为M2X=2.84,M2Y=1.79.     

LD-pumped passively Q-switched Nd:YVO4/YVO4 laser with an Nd3+:Cr4+:YAG saturable absorber

By using a piece of codoped Nd³⁺:Cr⁴⁺:YAG crystal as a saturable absorber, a laser-diode pumped passively Q-switched Nd:YVO₄/YVO₄ laser has been realized. The maximum laser output power of 2.452 W has been obtained at the incident pump power of 8.9 W for an 8.8% transmission of the output coupler at 1064 nm, corresponding to a slope efficiency of 30%. The other output laser characteristics of the laser have also been investigated. The laser with a Nd³⁺:Cr⁴⁺:YAG saturable absorber has a lower threshold pump power and a higher slope efficiency compared to that with a similar small-signal transmission of a Cr⁴⁺:YAG saturable absorber.     

High-power eye-safe KTA-OPO driven by YVO4/Nd:YVO4 composite laser

We present a high-power 1.53 μm laser based on intracavity KTA-OPO driven by diode-end-pumped acousto-optical Q-switched YVO₄/Nd:YVO₄ composite. The composite crystal was utilized for reducing the thermal effect, and the mode mismatch compensating OPO cavity was designed for efficient OPO conversion. The output power of eye-safe laser at 1535 nm was up to 4.4 W with the pump power of 27 W, corresponding to a diode-to-signal conversion efficiency of 16.3%. To our knowledge, this is the highest output power in diode-end-pumped circumstances. In the experiment, the strong yellow light generated by Raman conversion and frequency doubling in the KTA crystal was observed.     

Passively mode-locked 914-nm Nd:YVO4 laser

We demonstrate what is to our knowledge the first mode-locked Nd:YVO4 laser operating on the 4F3/2-4I9/2 transition at 914 nm. Using a semiconductor saturable-absorber mirror for passive mode locking, we have obtained 3-ps pulses at a repetition rate of 233.8 MHz. The laser is based on a standard delta cavity and is pumped by a Ti:sapphire laser. We obtained an average output power of 42 mW through one mirror and an accumulated output power of approximately 150 mW (through all cavity mirrors) at a pump power of 1.4 W.     

Study on optical characteristics of Nd:YVO4/YVO4 composite crystal laser

Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distributions in Nd:YVO4/YVO4 composite crystal and conventional crystal were analyzed and compared. The end-pumped Nd:YVO4/YVO4 composite crystal laser was designed and set up with z-cavity. The maximum output powers of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the incident pump power of 16.5 W. The highest optical-optical conversion efficiencies were up to 59.8% at 1064 nm and 37.2% at 532 nm respectively.     

Diode-end-pumped 1D top-hat Nd:YVO4 slab laser

A one-dimensional (1D) top-hat, diode-end-pumped, electro-optically Q-switched Nd:YVO4 slab laser is demonstrated. Under the pump power of 175.5 W, 26.3-W output power is obtained with the repetition rate of 5 kHz and the pulse width of 4.3 ns. The output beam has a good top-hat beam profile in both the near field and the far field.     

Tunable single and multiwavelength continuous-wave c-cut Nd:YVO4 laser

We report a discretely tunable, single and multiwavelength continuous-wave diode-end-pumped laser with a c-cut Nd:YVO₄ crystal lasing on the ⁴F_3/2?C⁴I_11/2 intermanifold transitions and an intracavity sub-THz free-spectral-range etalon. Experimental results show that it is tunable in the discrete regions of 1066.5?C1066.8, 1083.1?C1084.6, and 1087.2?C1088.2?nm and operates simultaneously at dual-wavelengths of (1084.6, 1087.4), (1066.5, 1088.0), (1066.8, 1083.3) nm by changing the angle of an intracavity etalon with 0.67 THz free-spectral range. With a proper etalon angle, the laser can also simultaneously oscillate at four wavelengths of 1066.9, 1082.9, 1085.7, and 1088.3?nm with a total output power of 1.2?W at an incident diode pump power of 15?W. Similar performance of the laser at different wavelengths was also achieved by using a 0.88?THz free-spectral-range etalon in the same laser cavity.     

A compact efficient continuous-wave self-frequency Raman laser with a composite YVO4/Nd:YVO4/YVO4 crystal

We report a low-threshold continuous-wave self-Raman laser with a composite YVO₄/Nd:YVO₄/YVO₄ crystal. The use of the composite crystal can reduce the thermal effects and achieve the low-threshold and high Raman output operation. The Raman threshold is as low as 2.2 W for the 808-nm diode pump. Under the pump of a diode power of 25.5 W, the highest Raman output of 2.8 W is obtained at 1175 nm, corresponding to a slope efficiency of 12% and a diode-to-Stokes optical conversion efficiency of 11%. The power fluctuation is less than 1.1% under the highest Raman output.     

cw dual-wavelength operation of a diode-end-pumped Nd:YVO4 laser

A dual-wavelength continuous wave (cw) diode-end-pumped Nd:YVO₄ laser that generates simultaneous laser action at the wavelengths 1064 nm and 1342 nm is demonstrated. The optimum oscillation condition for the simultaneous dual-wavelength operation in a diode-end-pumped solid-state laser has been derived. The relationship between the laser cavity and the output stability is also studied. Experimental results show that the stability of the output power at the two wavelengths could be enhanced by use of a three-mirror cavity. Received: 26 August 1999 / Revised version: 11 October 1999 / Published online: 23 February 2000     

Stable tunable single-frequency Nd:YAG laser

Single frequency operation of a Nd:YAG laser is obtained with a temperature-compensated, sealed intracavity etalon which is optimized with respect to selectivity and loss by taking spatial hole burning of the laser medium into account. For stabilization purposes we calculate the response of the laser when (i) the etalon's thickness is modulated and when (ii) the laser cavity length is modulated. We find orders of magnitude better stability for (i) and demonstrate the feasibility of a system with 100 mW output power, a longterm frequency stability of 3×10^?9, and an intensity stability of 10^?4.