A passively Q-switched diode pumped Yb:YAG microchip laser

A passively Q-switched diode pumped Yb:YAG microchip laser with Cr4+:YAG saturable absorber mirror is reported. The TEMoo laser pulses are obtained with 1,7-uJ pulse energy, 15-ns pulse width, 0.11-kW peak power, and a repetition rate of 2.2 kHz at 1049 nm. The doped concentration and dimension of Yb:YAG microchip crystal are 10 at.-% and 5×0.6 mm2, respectively.     

Efficient multiple-longitudinally diode laser pumped Nd:YAG slab laser

The operation of an eightfold longitudinally diode laser pumped 1.06m cw Nd:YAG slab laser is demonstrated. The 809 nm diode radiation is focused through a dichroic coating into each laser channel starting from the reflection points of the 1.06m beam in the slab crystal. At an absorbed pump power in the crystal of 2830 mW a maximum cw TEM₀₀ output of 1075 mW was achieved with a corresponding slope efficiency of 42.5%.     

100-W quasi-continuous-wave diode radially pumped microchip composite Yb:YAG laser

A diode radially pumped microchip Yb:YAG laser that consists of an Yb-doped core surrounded by undoped YAG of a slab shape is presented. Quasi-continuous-wave pumping of a 10-at. % Yb-doped core of 2 mmx2 mm square shape with pulses of 5-Hz repetition rate and 2.5% duty cycle delivers 66-W output peak power at 220-W input pump power with 0.49 slope efficiency. The best results, 112-W peak power with 0.63 slope efficiency and 0.38 optical-to-optical efficiency, were obtained with a 1.2 mmx1.2 mm square 15-at. % at Yb:YAG core.     

Efficient femtosecond optical parametric oscillator pumped by all solid-state mode-locking Yb:YCOB laser

We experimentally demonstrate a femtosecond optical parametric oscillator(OPO) synchronously pumped by a home-made solid-state mode-locking Yb:YCOB laser, which is capable of laser pulse as short as 102 fs and average power of 620 m W at the central wavelength of 1052 nm. By using a periodically poled lithium niobate with tuning of the grating periods from 28.5 to 31.5 μm as the nonlinear gain crystal, tunable femtosecond pulses from 1444 to 1683 nm are realized by conveniently adjusting the OPO cavity length with 76.8 MHz repetition rate. The maximum average output power is 152 m W at 1568 nm, corresponding to an idler power of 75 m W at 3197 nm as well as 36.6% total extraction efficiency.     

Efficient double-clad Yb3+-doped silica fibre laser pumped by an unfocused diode laser

A moderate output power Yb³⁺-doped double-clad fibre laser pumped by an unfocused diode laser is reported. This pumping configuration omits micro positioned lenses used in fibre coupled laser diodes, thus making the system significantly less complex and more robust. The maximum launch efficiency was ～80% and the maximum output power was >5 W with a measured FWHM of 18 pm.     

CW green laser at 520 nm based on sum-frequency mixing of diode pumped Yb:YAG laser

We report for the first time a continuous-wave (CW) green laser emission by sum-frequency mixing in Yb:YAG crystal. Using type-I critical phase-matching LBO crystal, a green laser at 520 nm is obtained by 1030 and 1048 nm intracavity sum-frequency mixing. The maximum laser output power of 269 mW is obtained when an incident pump laser of 17.8 W is used. At the output power level of 269 mW, the output stability is better than 3.2%.     

激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12 kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器（液氮温度）。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器(液氮温度)。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

Efficient CW Yb:YAG laser at 1048 nm under 968 nm diode laser pumping

We describe the output performances of the 1048 nm transition in Yb:YAG under in-band pumping with diode laser at the 968 nm wavelength. An end-pumped Yb:YAG crystal yielded 787 mW of continuous-wave (CW) output power for 9.1 W of absorbed pump power. Furthermore, 104 mW 524 nm green light was acquired by frequency doubling. Comparative results obtained for the pump with diode laser at 940 nm are given in order to prove the advantages of the in-band pumping.     

Doubly resonant continuous-wave optical parametric oscillator pumped by a single-mode diode laser

The performance characteristics of a doubly (signal and idler) resonant continuous-wave optical parametric oscillator based on periodically poled lithium niobate and pumped by a 100-mW single-mode laser diode at 810 nm are reported. Pump power thresholds as low as 16 mW and wavelength tuning over the range 1.15-1.25 microm at the signal and 2.31-2.66 microm at the idler were achieved through variation of crystal temperature, pump wavelength, and grating period. Up to 5 mW of signal output was obtained with the single-mode diode pump, and signal powers of up to 39 mW were obtained when pumping with a 400-mW injection-locked broad-area diode laser.     

Mode-locked Yb:KGW laser longitudinally pumped by polarization-coupled diode bars

Mode-locked operation of a simple Yb:KGW (potassium gadolinium tungstate) oscillator is described, providing 10 W at 1039 nm with a 290 fs pulse width. A polarization-coupled scheme is used for efficient longitudinal pumping by a pair of reshaped laser diode bars. With changes in cavity dispersion, the pulse width is adjustable from 134 to 433 fs, in a high-quality circular mode. A saturable absorber mirror provides self-starting operation, and the cavity is stabilized by the Kerr-lens effect.     

Efficient tunable Yb:YAG ceramic laser

A high-power efficient ceramic Yb:YAG laser was demonstrated at a room temperature of 20 °C with an Yb concentration of 9.8 at.%, a gain medium of 1 mm, a pumping power of 13.8 W, an output coupler of T = 10%, and a cavity length of 20 mm. A 6.8 W cw output power was obtained with a slope efficiency of 72%. The ceramic Yb:YAG laser exhibited a continuous tunability in the spectral range of 63.5 nm from 1020.1 to 1083.6 nm for T = 1% at a maximum output power of 1.6 W. To the best of our knowledge, this is the first study of the tunability of ceramic Yb:YAG lasers, except crystal Yb:YAG studies.     

Kerr-lens mode-locked polycrystalline Cr:ZnS femtosecond laser pumped by a monolithic Er:YAG laser

We demonstrated a Kerr-lens mode-locked polycrystalline Cr:ZnS laser pumped by a narrow-linewidth linearpolarised monolithic Er:YAG nonplanar ring oscillator operated at 1645 nm. With a 5-mm-thick sapphire plate for intracavity dispersion compensation, a compact and stable Kerr-lens mode-locking operation was realised. The oscillator delivered 125-fs pulses at 2347 nm with an average power of 80 m W. Owing to the special polycrystalline structure of the Cr:ZnS crystal, the second to fourth harmonic generation was observed by random quasi-phase-matching.     

100W二极管泵浦Nd:YAG薄片激光器

报道了一台高效率二极管泵浦Nd:YAG薄片激光器,采用高效均匀泵浦耦合技术,在峰值功率1.008kW,占空比25％, 电-光效率大于45%的二极管激光阵列泵浦下,用一块1mm厚的Nd:YAG薄片激光介质,获得了峰值功率404W,平均功率101W的准连续激光输出,光-光效率达到40%,电-光效率超过18%。     

Diode-pumped Kerr-lens mode-locked femtosecond Yb:YAG ceramic laser

We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser based on an Yb:YAG ceramic. Stable laser pulses with 97-fs duration, 2.8-nJ pulse energy, and 320-mW average power were obtained. The femtosecond oscillator operated at a central wavelength of 1049 nm and a repetition rate of 115 MHz. To the best of our knowledge, this is the first demonstration of a Kerr-lens mode-locked operation in a diode-pumped Yb:YAG ceramic laser with sub-100 fs pulse duration.     

Continuous-wave and Q-switched performance of an Yb:YAG/YAG composite thin disk ceramic laser pumped with 970-nm laser diode

Using front face-pumped compact active mirror laser （CAMIL） structure, we have demonstrated an Yb：YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave （CW） and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Q- switched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.     

激光二极管端面泵浦Yb:YAG圆棒热效应研究

基于激光二极管端面泵浦Yb∶YAG棒工作特点的分析,提出了端面绝热、周边恒温的激光晶体热分析模型,采用了一种新的热传导方程求解方法,得到了超高斯光束端面泵浦Yb∶YAG棒温度场的一般解析表达式。同时分析了不同阶次、不同光斑半径、不同功率超高斯光束以及晶体参数改变时对于Yb∶YAG棒温度场分布的影响。研究结果表明,若准直聚焦到Yb∶YAG棒泵浦面42.5W的光束具有4阶超高斯强度分布时,掺Yb3+质量分数为10.0at.%、长度为2.5mm、半径为2mm的Yb∶YAG棒的泵浦面获得74.20℃的最高温升。新的热传导方程求解方法在研究激光棒温度场分布方面具有计算量小、精度高等特点。研究结果对减小激光晶体的热效应,提高全固态Yb∶YAG激光器性能提供了理论依据。     

Efficient quasi-three-level Nd:YAG laser at 946 nm pumped by a tunable external cavity tapered diode laser

Using a tunable external cavity tapered diode laser (ECDL) pumped quasi-three-level Nd:YAG laser, a fivefold reduction in threshold and twofold increase in slope efficiency is demonstrated when compared to a traditional broad area diode laser pump source. A TEM₀₀ power of 800 mW with 65% slope efficiency is obtained, the highest reported TEM₀₀ power from any 946 nm Nd:YAG laser pumped by a single emitter diode laser pump source. A quantum efficiency of 0.85 has been estimated from experimental data using a simple quasi-three-level model. The reported value is in good agreement with published values, suggesting that the model is adequate. Improvement of the 946 nm laser due to the ECDL's narrow spectrum proves to be less significant when compared to its spatial quality, inferring a broad spectrum tapered diode laser pump source may be most practical. Experimental confirmation of such setup is given.     

Characteristics of a continuous-wave Yb:GdVO4 laser end pumped by a high-power diode

An efficient and compact diode-pumped continuous-wave Yb:GdVO4 laser is demonstrated, generating an output power of 4.0 W with an optical conversion efficiency of 61% and a slope efficiency as high as 78%. With increasing pump power the polarization of the laser output changes from sigma to pi, while in a certain intermediate power range the two polarization states coexist with different emission wavelengths.     

Efficient mechanically Q-switched diode side pumped Nd:YAG laser using a rotating prism and mirror combination

In this paper the construction of a mechanically Q-switched diode side pumped Nd:YAG laser system is described. It consists of a 50 cm long plane-plane resonator Q-switched with a combination of a rotating prism and a mirror. With an optical to optical efficiency of 25% Q-switched pulses (@1064) of 48 mJ and 8 ns are obtained at a rep-rate of 30 Hz with an output in near TEMoo mode. At a peak power of 6 MW the M ² value is found to be 1.92. The laser is frequency doubled and then tested on a 50 ??m thick tantalum foil which results in circular holes of diameter 13 ??m in it.