Diode-Pumped Self-Q-Switched Cr,Nd：YAG Laser with High Average Output Power

A diode end-pumped self-Q-switched Cr,Nd:YAG laser was established with pulse duration in the range of 8-10ns. The maximum average output power was 4.4 W and the slope efficiency was 27% using an output coupler of R=70%. At pumping power of 17.4 W the laser produces high-quality pulses at 1064 nm in a TEMoo-mode.     

Diode-Pumped Passive Q-Switched 946-nm Nd：YAG Laser with 2.1-W Average Output Power

We demonstrate a diode-pumped passive Q-switched 946nm Nd: YAG laser with a diffusion-bonded composite laser rod and a co-doped Nd, Cr:YAG as saturable absorber. The average output power of 2.1 W is generated at an incident pump power of 14.3 W. The peak power of the Q-switched pulse is 643 W with 80kHz repetition rate and 40.8 ns pulse width. The slope efficiency and optical conversion efficiency are 17.6% and 14.7%, respectively.     

Diode-Pumped Quasi-Three-Level Passively Q-Switched Nd：GGG Laser with a Codoped Nd,Cr：YAG Saturable Absorber

We demonstrate the first quasi-three-level passively Q-switched Nd：GGG laser at 937nm using a Nd, Cr：YAG crystal as the saturable absorber. The dependences of the average output power, the repetition rate and the pulse width on the incident pump power are obtained. A maximum average output power of 1.18 W with repetition rate of 35kHz and pulse width of 45ns is achieved at an incident pump power of 18.3 W. The corresponding optical-to-optical and slope efficiencies are 6% and 10%, respectively.     

Diode-Pumped Self-Starting Mode-Locked Nd：YVO4 Laser with Semiconductor Saturable Absorber Output Coupler

By using a semiconductor saturable-absorber output coupler as a mode-locking device, we experimentally realized the operation of a diode-pumped passively mode-locked Nd:YVO4 laser. Stable laser pulses with duration of 2.3ps were generated at the output power of about 1W. With increasing the pump power to 9 W, the maximum mode-locked power of 1.7 W was obtained, which corresponds to a slope conversion efficiency of 44 % and opticalto-optical conversion efficiency of 19%.     

Investigation on Performance of High Repetition Diode-Pumped Heat-Capacity Nd：YAG Laser

We demonstrate the improvements of both beam quality and thermal depolarization loss of an all-solid-state heat-capacity Nd:YAG laser with repetition rate of 50Hz, for the first time to our best knowledge, compared with the conventional steady-state laser. The beam quality of the heat-capacity laser has been improved three times higher than the conventional steady-state laser within the lasing periods of 60s. The depolarization loss caused by thermo-optical effects which is definitely considerable in steady-state Nd:YAG laser has almost not been observed under heat-capacity operation. Design and operations of the all-solid-state heat-capacity Nd: YAG laser with average output power of 25 W with repetition 50 Hz are also studied with the optical-to-optical efficiency of 33.3%.     

Generation of 2.1 W Continuous Wave Blue Light by Intracavity Doubling of a Diode-End-Pumped Nd：YAG Laser in a 30 mm LBO

A folded four-mirror cavity with a composite Nd：YAG rod is optimized to obtain high efficient cw 473nm blue output. The laser could operate stably in the region of the thermal-lens focal length from 20mm to 70mm. LBO is used for intracavity frequency doubling of the 946nm transition of Nd：YAG and the optimum LBO length is investigated. A maximum output power of 2.1 Win the blue spectral range at 473nm is achieved with 30-mm-long LBO, corresponding to an optical conversion efficiency of 9.1%.     

Intracavity—Doubled Self—Q—Switched Nd,Cr：YAG 946／473nm Microchip Laser

We carried out the operation of an intracavity frequency-doubled self-Q-switched Nd,Cr:YAG/NHbO3 946/473nm microchip laser pumped by a Ti:sapphire laser.The overall cavity length was about 4mm.The maximum average blue power of 12mW was achieved with a repetition rate of 13kHz at an absorbed pump ower of 545mW.The pulses of the 473nm laser had a duration of 7ns and a peak power of 132W at this pump level.The conversion efficiency was 2.2% with respect to the absorbed pump power of a 808nm laser.     

Diode-Pumped Passive Q-Switched 946 nm Nd：YAG Laser with a GaAs Saturable Absorber

We report, for the first time to our knowledge, a diode-pumped passive Q-switched 946nm Nd：YAG laser by using a GaAs as saturable absorber. The maximum average output power is 1.24 W at an incident pump power of 15 W, corresponding to a slope efficiency of 10%. Laser pulses with pulse duration of 70ns and repetition rate of 330 kHz are generated.     

High Power Diode-End-Pumped Nd：YAG 946-nm Laser and Its Efficient Frequency Doubling

We report a high power operation of the ^4Fa/2 → ^4I9/2 transition in diode-end-pumped laser at 946nm. The maximum output of 5.1 W is obtained with a short linear plano-concave cavity, and the slope efficiency is 24.5% at incident pump power of 23.3 W. To our knowledge, this is the highest value of the LD-pumped Nd:YAG 946 nm lasers that employ the conversional Nd:YAG rod as the gain medium. By intracavity frequency doubling with an LBO crystal, up to 982mW cw output power in the blue spectral range at 473nm is achieved at an incident pump power of 10.9 W with a compact three-element cavity, leading to optical-to-optical conversion efficiency of 9%. The conversion efficiency should be increased to 15.1%, if the rather low absorption coefficient of this Nd:YAG is considered.     

A Bidirectional, Diode-Pumped, Passively Mode-Locked Nd：YVO4 Ring Laser with a Low-Temperature-Grown Semiconductor Saturable Absorber Mirror

We report the operation of a bidirectional picosecond pulsed ring Nd：YVO4 laser based on a low-temperaturegrown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5 MHz, pulse duration of 81 ps, power of 2 × 200 mW.     

Green-Beam Generation of 40W by Use of an Intracavity Frequency-Doubled Diode Side-Pumped Nd:YAG Laser

A cw diode side-pumped Nd：YAO laser is frequency doubled to 532nm with an intracavity KTP crystal in a Vshaped arrangement, achieving an output power of 40 W corresponding to an optical-optical conversion efficiency of 9.7%. The instabilities and the M2-parameters of the laser are measured at different output powers after the beam is filtered.     

Stable High Power and High Beam Quality Diode-Side-Pumped Continuous-Wave Intracavity Frequency-Doubled Nd:YAG Laser

We report a stable high power and high beam quality diode-side-pumped cw green laser from intracavity frequency-doubled Nd： YAG laser with KTP. By using a L-shaped concave-convex resonator, designed with two Nd：YAG rods birefringence compensation, a large fundamental mode size in the laser crystal and a tight focus in the nonlinear crystal could be obtained simultaneously. The green laser delivers a maximum 532nm output power of 23.2 W. Under 532nm output power of 20.9 W, the beam quality factor is measured to be 4.1, and the fluctuation of the output power is less than 1.4% in an hour.     

Intracavity frequency-tripling of actively mode-locked diode-pumped Nd:YAG laser

We report the first diode-pumped solid-state laser operating in cw-mode-locked regime and simultaneously achieving intracavity frequency-tripling. This laser provide UV picosecond pulses (λ=355 nm) of 10 ps duration with 0.5 mW average power at 150 MHz repetition rate. A different set of adjustments gave rise to a Q-switched mode-locked regime. Trains of hundred UV pulses of 60 ps duration and 4 W peak power were produced in this latter case at 50 kHz repetition rate. Received: 12 October 1998 / Revised version: 12 December 1998 / Published online: 26 May 1999     

Simultaneous Generation of Multi-Wavelength Laser from Nd:YAG Crystals in a Cruciform Cavity

A cruciform cavity is presented for multi-wavelength laser generation. On the basis of considering the optimal power ratio and good spatial overlap of the two fundamental beams, the maximum output power of 589 nm laser reaches 3.5 W when the pumping power of Nd：YAG A and Nd：YAG B are 311.5 W and 261.8 W, respectively. At the same time, the other wavelength lasers are also obtained with the output power distribution of 2.5 W at 66Onto, 15 W at 532nm, lOOmW at 1319nm and 240mW at 1064nm. The corresponding beam quality factors are M^2 x = 4.93, M^2 y = 5.01 at 589nm, M^2z = 4.51, M^2 y = 4.85 at 660hm, and M^2 x = 4.12, M^2 y = 3.96 at 532nm, respectively. The instabilities of the three visible lights are measured, which are also less than 2% within three hours.     

Observation of Antiphase State in a Self-Q-switched Nd,Cr:YAG Laser

We experimentally investigate the antiphase dynamics phenomenon in a self-Q-switched Nd, Cr：YAG laser operating at 946 nm. Due to the effect of spatial hole burning, the Q-switched pulses sequences of one, two and three modes at different pump power are observed. The experimental results show that the pulse sequences display classic antiphase dynamics.     

A 4.8-W M^2 = 4.6 Continuous-Wave Intracavity Sum-Frequency Diode-Pumped Solid-State Yellow Laser

A yellow continuous wave with beam quality M^2= 4.6 and output power of 4.8 W at 589nm is generated by intracavity sum-frequency mixing of 1064 nm and 1319 nm radiations of a Nd：YAG laser. To achieve high beam quality at high power, thermally near-unstable flat-flat resonators with two-rod birefringence compensation are designed to obtain the large fundamental mode size inside the Nd：YAG rods and the same beam width inside the KTP crystal. The optimal intracavity power ratio of both 1064nm and 1319nm beams is also considered. The output power fluctuation of the yellow laser remains less than 5% in four hours.     

104 W内腔倍频全固态Nd:YAG绿光激光器

报道了一台高功率内腔倍频全固态Nd:YAG绿光激光器,针对KTP晶体热效应和激光热稳定腔,采取了对KTP晶体进行低温冷却的优化措施,以便减少KTP晶体的热效应导致的相位失配,同时兼顾了Nd:YAG棒的热致双折射效应和KTP晶体热透镜效应,设计了热稳定谐振腔;实验中采用80个20 W激光二极管阵列侧面抽运Nd:YAG棒和Ⅱ类相位匹配KTP晶体(在27℃时相位匹配角为φ=23.6°;θ=90°,尺寸为7 mm×7 mm×10 mm)内腔倍频技术,谐振腔腔长为530 mm,KTP晶体的冷却温度为4.3 ℃,抽运电流为18.3 A时,实现平均功率达104 W、脉冲宽度为130 ns的532 nm激光输出;其重复频率为20.7 kHz.光-光转换效率为10.2%.     

104W内腔倍频全固态Nd∶YAG绿光激光器

报道了一台高功率内腔倍频全固态Nd∶YAG绿光激光器 ,针对KTP晶体热效应和激光热稳定腔 ,采取了对KTP晶体进行低温冷却的优化措施 ,以便减少KTP晶体的热效应导致的相位失配 ,同时兼顾了Nd∶YAG棒的热致双折射效应和KTP晶体热透镜效应 ,设计了热稳定谐振腔 ;实验中采用 80个 2 0W激光二极管阵列侧面抽运Nd∶YAG棒和Ⅱ类相位匹配KTP晶体 (在 2 7℃时相位匹配角为 =2 3.6° ;θ =90° ,尺寸为 7mm× 7mm× 10mm)内腔倍频技术 ,谐振腔腔长为 5 30mm ,KTP晶体的冷却温度为 4 .3℃ ,抽运电流为 18.3A时 ,实现平均功率达 10 4W、脉冲宽度为 130ns的 5 32nm激光输出 ;其重复频率为 2 0 .7kHz。光光转换效率为 10 .2 %。