Passive Q-switching of erbium glass laser by magnesium aluminosilicate sitall with cobalt ions

We have studied the radiation output parameters for an erbium glass laser, lasing at a wavelength of 1.54 μm, with passive Q-switching by means of a cobalt-containing magnesium aluminosilicate sitall compared with a saturable absorber based on a magnesium aluminum spinel crystal with cobalt ions. We have shown that the output characteristics of the laser emission when using sitall are not inferior to the analogous characteristics of a laser based on a spinel crystal, and are practically independent of the temperature of the saturable absorber in the range 0°C–80°C. The duration (energy) of the output pulses was 70 nsec (∼4 mJ), the energy dispersion of the radiation pulse relative to the average value was no greater than 3%, the beam divergence was 2.8 mrad, the laser beam quality factor was M² = 1.2. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 126–131, January–February, 2007.     

电光调Q驱动电源与晶体之间的引线研究

分析了高重频电光调Q驱动电源与晶体之间的最佳引线。由于调Q晶体和引线都存在分布电容和电感,如果晶体两端阻抗不匹配,电压脉冲就会出现阻尼振荡,从而影响激光脉冲。针对这一问题,使用脉冲反射法和分布参数电路法,以平行导线作为引线,分析了脉冲在引线中的传输、晶体高压波形和引线所要求的驱动电源的最小功率。使用脉冲反射法,以同轴线作为引线,分析了简单连接晶体和阻抗匹配后连接晶体的两种情况,得出了晶体两端电压波形和同轴引线阻抗匹配后的电路对快速开关的要求。根据以上分析,得出了电光调Q中引线的选择原则。     

Q-Switched Thulium-Doped Fiber Laser with Pure Titanium-Film-Based Saturable Absorber

ABSTRACT

We demonstrate the generation of Q-switching pulse train in thulium-doped fiber laser (TDFL) cavity by employing titanium-based saturable absorber (Ti-SA). The Ti-SA was fabricated by depositing titanium particles molecules using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) film. Subsequently, stable Q-switched pulses were obtained within the 1,552 nm pump power range from 272.1 to 467 mW, with repetition rate tuned from 21.8 to 39.1 kHz. At the maximum pump power, the TDFL showed that the pulse duration of 2.22 μs and the maximum pulse energy of 124 nJ.     

半导体可饱和吸收镜作为被动调Q吸收体的发展状况

简介了近年来发展起来的若干种新型固体激光器被动调Q用吸收体：掺Cr4+系列，Cr，Nd∶YAG自调Q激光晶体，人眼安全激光器被动调Q用吸收体，GaAs吸收体，半导体可饱和吸收镜。着重介绍了固体激光器和光纤激光器调Q用半导体可饱和吸收镜的原理、研制方法及应用状况。     

Diode-laser pumped passively Q-switched green laser by intracavity frequency-doubling with periodically poled LiNbO3

A continuous-wave (CW) laser-diode (LD) pumped passively Q-switched intra-cavity frequency-doubling green laser is reported in this paper. We used 3% at Nd doped YVO₄ as gain medium, Cr⁴⁺:YAG as a saturable absorber for passively Q-switch and periodically poled LiNbO₃ (PPLN) as a frequency doubler. The output energy of the green laser is 1.96 μJ with the pulse-width of 15.6 ns. No green-noise problem exists in the green laser. Some theoretical results on the passive Q-switching and intra-cavity frequency-doubling are also discussed.     

考虑激光下能级弛豫过程的调Q Nd∶YAG 速率方程理论分析

本文比较了考虑与不考虑激光下能级弛豫过程的两种形式的调Q速率方程，并以二极管激光侧面泵浦电光调QNd∶ YAG为例，分别采用两种形式的调Q速率方程，分析了调Q过程中上、下能级粒子数变化过程，计算了输出调Q激光脉冲波形、峰值功率以及能量，进行了比较分析，并解释了调Q“子脉冲”与拖尾现象.     

半导体激光泵浦锁模调QNd：YAG板条激光器

报道准连续６０Ｗ半导体激光二极管侧面泵浦的锁模调ＱＮｄ：ＹＡＧ板条激光器，调Ｑ锁模的激光脉冲宽度（ＦＷＨＭ）为６０ｐｓ，调Ｑ脉冲包络宽度为２５０ｎｓ，积分能量１６３μＪ，最大锁模脉冲的峰值功率超过１００ｋＷ。     

A compact graphene Q-switched erbium-doped fiber laser using optical circulator and tunable fiber Bragg grating

We demonstrate a passively Q-switched tunable erbium-doped fiber laser(EDFL)based on graphene as a saturable absorber(SA).A three-port optical circulator(OC)and a strain-induced tunable fiber Bragg grating(TFBG)are used as the two end mirrors in an all-fiber linear cavity.The Q-switched EDFL has a low pump threshold of 23.8 mW.The pulse repetition rate of the fiber laser can be widely changed from 9.3 kHz to 69.7 kHz by increasing the pump power from23.8 mW to 219.9 mW.The minimum pulse duration is 1.7μs and the highest pulse energy is 25.4 nJ.The emission wavelength of the laser can be tuned from 1560.43 nm to 1566.27 nm by changing the central wavelength of the straininduced TFBG.     

Multi-Wavelength Q-Switched Ytterbium-Doped Fiber Laser with Multi-Walled Carbon Nanotubes

We demonstrate a passively multi-wavelength Q-switched Ytterbium-doped fiber laser (YDFL) based on a multi-wall carbon nanotubes embedded in polyethylene oxide film as saturable absorber. The YDFL generates a stable multi-wavelength with spacing of 1.9 nm as the 980 nm pump power is fixed within 62. 4 mW and 78.0 mW. The repetition rate of the laser is tunable from 10.41 to 29.04 kHz by increasing the pump power from the threshold power of 62.4 mW to 78 mW. At 78 mW pump power, the maximum pulse energy of 38 nJ and the shortest pulse width of 8.87 µs are obtained.     

一种快速有效的NQR探头恢复方法

介绍了一种用于主动减小NQR探头恢复时间的Q值变换电路,它利用MOEFET控制变Q电路与探头电路的耦合,并通过变压器增加与电感线圈串联的阻抗值以达到改变Q值的目的. 此电路不会产生新的振铃也不会对接收NQR的分辨率造成损失. 实验结果表明,电路能有效缩短探头的恢复时间,同时还可以提高信噪比.