Effect of output coupling ratio on the performance of ring-cavity Brillouin fiber laser

We present a single-wavelength Brillouin fiber laser utilizing a ring-cavity configuration. Performances and characteristics of the laser system have been investigated at different output coupling ratios. The optimum output power of the system stood at 7.3 mW, which was obtained at 90% output coupling ratio. A low Brillouin threshold power of 0.9 mW was obtained at 10% output coupling ratio when the Brillouin pump was set at its maximum power of 24 mW.     

半导体激光泵浦的Nd:YVO4激光器的1.064 μm高效率连续输出

报道了半导体激光端面泵浦的Nd:YVO4激光器获得线偏振的1.064 μｍ激光高效率连续稳定输出。在半导体激光功率为1.5 W时，获得连续输出功率为837 kW的TEM00模，激光器泵浦阈值功率为140 kW，斜率效率达61.5％，光-光转换效率达56％，电-光转换效率达15％。     

Diode pumped operation of 1 mm Tm,Ho:YAP microchip laser

A single-longitudinal-mode (SLM) operation of a c-cut 1 mm Tm(5%), Ho(0.3%):YAP micro-chip laser pumped by a fiber-coupled diode-laser was reported. Under cryogenic temperature, the output power of 216 mW was obtained under the incident power of 2230 mW, corresponding to the slope efficiency was 13.6%. As much as 133 mW output and slope efficiency of 4.9% was obtained under the pump power of 3000 mW at 291 K. In addition, a maximum SLM output power of 30 mW at wavelength of 2130.56 nm is demonstrated under 77 K.     

Diode pumped operation of tm,Ho:YAP microchip laser

Single-wave length operation of a c-cut Tm (5%), Ho (0.3%):YAP microchip laser pumped by a fiber-coup led diode-laser was reported. Under cryogenic temperature, the output power of 188 mW was obtained under the incident power of 2230 mW, corresponding to the slope efficiency was 12.2%. As much as 168 mW output and slope efficiency of 5.7% was obtained under the pump power of 3400 mW at 291 K. In addition, a maximum single-wave length output power of 60 mW at wavelength of 2130.2 nm and 14 mW at wavelength of 2102.4 nm is demonstrated under 77 and 291 K, respectively.     

Laser performance of Nd:LaB3O6 cleavage microchips passively Q-switched with a Cr4+:YAG saturable absorber

Passively Q-switched laser oscillation at 1060 nm from an unprocessed Nd:LaB₃O₆ cleavage microchip with a Cr⁴⁺:YAG saturable absorber has been demonstrated. The influence of absorbed pump power, output coupler transmission and cavity length on the output pulse characteristics has been investigated. For a plano-concave cavity with a cavity length of 28 mm, pulse with 100 mW average output power, 4.0 μJ energy, 17 ns duration, 25 kHz repetition rate, and 0.24 kW, peak power was obtained at the absorbed pump power of 1.42 W and output coupler transmission of 3.5%. For a plano-plano cavity with a cavity length of 5 mm, pulse with 85 mW average output power, 2.1 μJ energy, 2.3 ns duration, 40 kHz repetition rate, and 0.89 kW, peak power was obtained at the absorbed pump power of 1.42 W and output coupler transmission of 5.6%. Because a chopper with a 5% duty cycle was employed in the experiments to reduce the influence of pump-induced thermal loading, the above average output powers were obtained at the 5% duty cycle and extrapolated to 100%.PACS 42.55.Rz; 42.60.Gd; 42.70.Hj     

Initial operation of a higher-power quasi-optical gyrotron

Results from the initial operation of a high-power quasi-optical gyrotron based on the 90-kV, 50-A Varian VUW-8144 electron gun are reported. The output power and efficiency have been measured for a resonator mirror separation of 19.4 cm with a magnetic field of 4.95 T, corresponding to resonator output coupling of 1.9%, and for a resonator mirror separation of 21.4 cm with a magnetic field of 4.7 T, corresponding to a resonator output coupling of 3.1%. Operation was multimoded with 3-6 modes excited in the range of 125-130 GHz for the 4.95-T magnetic field. A peak efficiency of 15% at an output power of 161 kW was obtained for a gun voltage of 93 kV and a current of 12 A. A peak-output power of 364 kW at an efficiency of 10% was obtained at a voltage of 95.6 kV and 37.5 A     

新颖的双通道输出高功率掺铒光纤宽带光源

在分析L波段放大自发辐射(ASE)谱产生原理的基础上,设计出一种新颖的双级结构掺铒光纤ASE宽带光源,该光源可在两个端口分别输出高功率的C波段和L波段的ASE谱.设计将C波段ASE谱注入到掺铒光纤中作为L波段ASE谱的二次抽运源,使得L波段ASE谱功率得到了有效提高.优化光源结构参量后从两个端口分别获得了12.97 dBm和12.81 dBm的C波段和L波段ASE宽带谱.将两个输出端口组合得到了功率为15.9 dBm,泵浦转换效率达到21.6%的C+L波段超宽带ASE光源.     

CONTINUOUS-WAVE LASER OSCILLATION OF Yb:FAP CRYSTALS AT A WAVELENGTH OF 1043nm

A continuous-wave laser oscillation was demonstrated with a Yb-doped fluorapatite (FAP) crystal pumped with a 905 nm Ti:sapphire laser. The output characteristics for different output couplers were investigated. A maximum power of 67mW at a 1043nm wavelength was obtained with 10% output coupler, pumped by a Ti:sapphire laser with 910mW power. This corresponds to a slope efficiency of 26.5%.     

Output-coupling-dependent polarization state of a continuous-wave Yb:YCa4O(BO3)3 laser

High-power continuous-wave laser operation was demonstrated with a y-cut Yb:YCa(4)O(BO(3))(3) crystal, showing critical dependence on the output coupler used. Polarized laser oscillation with E||x was obtained at 1085.6 nm by using a coupler of 0.5% transmission, yielding an output power of 7.3 W with an optical-to-optical efficiency of 63%. Higher output couplings (>/=2%) led to polarized oscillation with E||z at laser wavelengths 相似文献   

1018 nm短波长掺镱光纤激光高功率自组织相干合成

搭建了两台高功率、低量子损耗的1018 nm短波长掺镱光纤激光器,进行了全光纤结构下两路光纤激光器的相干合成实验。获得了功率为55 W、合成效率为90.2%的相干输出,这是当前严格单模1018 nm光纤激光器的最高功率水平。同时,验证了Michelson腔自组织相干合成技术能够实现光纤激光器的高功率单模输出。     

Efficient single-mode operation of a standing-wave dye laser

The selection of a single longitudinal mode of a dye laser can be achieved with double or triple Michelson reflectors instead of Fabry-Perot etalons inside the laser cavity. These systems can be adapted to commercial multimode dye lasers. They provide a high efficiency and a good geometrical quality of the output beam. With a 7 watt pump power (λ=514.5 nm line of the Ar⁺ laser), a tunable output power of 1 watt was obtained at the peak of R6G, in the main output beam; the total single-mode power, including the auxiliary output beams, exceeded 1.4 watt. These results correspond to efficiencies of 14% and 20%, respectively (24% and 30% slope efficiencies). We discuss in the text why these efficiencies are comparable to those of ring lasers. In the infrared, with a 4.5 watt pump power (red lines of a Kr⁺ laser), 250 mW of single-mode output power in the main output beam was obtained at 780 nm with Oxazine 750.     

Phase locking of two beams emitting from a side pumped Nd:YAG slab with self-imaging resonator

Intracavity phase locking of two beams emitting from a block of Nd:YAG medium side-pumped by laser diode array (LDA) was investigated experimentally. The interference fringes of the two beams occured at the output mirror. The coherent output power of 1.13 W was obtained with combination efficiency of 64.9% and coherence degree of about 60%. Only a metallic wire as a filter located at a suitable position close to the output mirror can efficiently lock the entire structure with less than 8% power loss.     

A frequency-doubled pulsed chemical oxygen-iodine laser

The intracavity second-harmonic generation of pulsed chemical oxygen-iodine laser radiation was investigated. A pulsed chemical oxygen-iodine laser with a maximum output energy of 6.14 mJ was used. The second-harmonic output of 0.5 mJ was demonstrated using a lithium iodate crystal. The conversion efficiency of 8% was limited by intracavity losses. Numerical simulation predicts that a conversion efficiency of 75% can be obtained with 1% intracavity losses.     

Efficient Tm:YLF laser with a volume Bragg grating recycle pumped by laser diode

By using a pump recycling configuration, we presented a high efficient diode-pumped Tm:YLF laser with a volume Bragg grating. When the incident pump power was 33.1 W, a maximum output power of 11.1 W at 1907.8 nm with full width at half maximum of 0.6 nm was obtained. The slope efficiency with respect to the incident pump power was 44.8%, and the optical-to-optical efficiency was 33.5%. In addition, the VBG-based Tm:YLF laser was employed as a pumping source of Ho:YAG laser, the maximum output power of 4.7 W with a slope efficiency of 67.0% was obtained, corresponding to Tm-to-Ho conversion efficiency of 51.6%.     

Influence of neodymium concentration on the strength of thermal effects in continuous-wave diode-pumped Nd:YVO4 lasers at 1064 nm

The influence of neodymium ion concentration on the continuous-wave power performance of diode-pumped Nd:YVO₄ lasers was experimentally investigated by using three crystals of approximately the same total absorption but different Nd concentrations of 0.5, 1, and 3 at.%. In situ measurements indicate that strong thermal lensing occurs in the highly doped sample (3 at.% Nd) and precludes scaling of the output power to large values. Results also show that undesirable thermal effects are dramatically reduced with decreasing active-ion concentration. The best power performance was obtained with a 10-mm-long Nd:YVO₄ sample that had 0.5 at.% Nd. In this case, up to 6.5 W of continuous-wave output power was obtained at 1064 nm by using a 3% transmitting output coupler.     

Efficient GTR-KTP IOPO driven by a diode-pumped Nd:YAG/Cr4+:YAG laser with the shared cavity configuration

An efficient eye-safe GTR-KTP IOPO with the shared cavity configuration and excited by a diode-end-pumped composite Nd:YAG/Cr⁴⁺:YAG laser was demonstrated. Under the incident LD power of 8.4 W, the maximum average output power of 900 mW at 1572 nm was obtained with the T=33% output coupler, corresponding to a diode-to-signal conversion efficiency of 10.7%. The corresponding signal pulse width and repetition rate were respectively 2.2 ns and 12 kHz, with the peak power and single pulse energy estimated to be 34.1 kW and 75 μJ, respectively. The instability of the average signal output power over hours-long operation was found to be 2.0%. As for the common KTP IOPO at the same pump condition and cavity design, a lower average output power of 640 mW with a longer pulse width of 4.6 ns was obtained. The corresponding diode-to-signal conversion efficiency was reduced by 28.8% compared with that obtained in GTR-KTP IOPO. A theoretical model for the compact GTR-KTP IOPO was also presented in this paper. Theoretical analysis on the pulse characteristics of the signal was performed, which showed a good agreement with that obtained experimentally.     

Blue laser via IR resonant doubling with 71% fiber to fiber efficiency

We report on high efficiency resonant doubling to 486 nm using periodically poled KTP. The IR laser source is an FBG stabilized semiconductor laser with a maximum polarization maintaining (PM) fiber coupled output of 840 mW. An output power of 680 mW at 486 nm was obtained from our optimized cavity, giving net efficiency of 81%. Also, we report an 87.5% net efficiency in coupling of this blue light from the servo locked cavity into a single-mode PM fiber. This gives a total of 71% fiber to fiber efficiency. Furthermore, a wall plug efficiency of 21.4% was obtained.     

Watt-level Pr~(3+):YLF deep red laser pumped by a fiber-coupled blue LD module or a single-emitter blue LD

A power-scaled laser operation of Pr:YLi F4(YLF)crystal at 720.9 nm pumped by a 443.6 nm laser diode(LD)module was demonstrated.The 20 W module was used to pump the Pr:YLF crystal,and a maximum output power of 3.03 W with slope efficiency of 30.04%was obtained.In addition,a 5 W blue LD was also used to pump the Pr:YLF laser,and a maximum output power of 0.72 W was obtained at room temperature.The output power was limited by the wavelength mismatch between the single-emitter LD and the absorption peak of the crystal.     

Efficient continuous wave and Q-switched operation of a dual-end-pumped <Emphasis Type="Italic">c</Emphasis>-cut Tm:YAP laser

An efficient continuous wave (CW) and Q-switched c-cut Tm:YAP laser is reported in this letter. With the dual-end-pumped convex-concave resonator, CW output power up to 13.6 W at 1.99 μm was obtained under a total incident pump power of 50 W. The corresponding slope efficiency was 34.3% and conversion efficiency was 27.2%. The active Q-switched operation of the laser had an average output power of 12.5 W at 10 kHz pulse repetition frequency, with a minimum pulse width of 126 ns. With 6 kHz pulse repetition frequency, the maximum pulse energy of 1.6 mJ was obtained. In addition, using the Tm:YAP laser as a pumping source for gain-switched Cr:ZnSe laser, as much as 4 W output power in the wavelength range of 2.5–2.6 μm was obtained.     

High peak power Nd:YAG laser pumped by 600-W diode laser stack

The Q-switched laser with triangle slab made of Nd:YAG crystal side pumped by 600-W quasi-cw diode laser stack has been designed. The multimode (M²≈2.6) output energy of about 42 mJ was demonstrated in free running mode for110-mJ pump energy. In Q-switch experiments, the KDDP Pockels cell was placed between the slab and rear mirror in plane-plane cavity with output coupler of 84% transmission. The energy of 8 mJ in 2.1-ns pulse duration was obtained for near TEM₀₀ output beam. For passive Q-switching by means of Cr:YAG crystal of 12.6% unsaturated transmission, the energy of 5.1 mJ in 2.5-ns pulse duration was obtained for output beam close to TEM₀₀ mode.