Judd--Ofelt analysis of spectra and experimental evaluation of laser performance of Tm3+ doped Lu2SiO5 crystal

This paper reports that the Tm^3＋：Lu2SiO5 （Tm：LSO） crystal is grown by Czochralski technique. The roomtemperature absorption spectra of Tm：LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Ω2=9.3155×10^-20 cm^2, Ω4=8.4103×10^-20 cm^2, Ω6=1.5908×10^-20 cm^2, the fluorescence lifetime is calculated to be 2.03 ms for ^3F4 → ^3H6 transition, and the integrated emission cross section is 5.81×10^-18 cm^2. Room-temperature laser action near 2μm under diode pumping is experimentally evaluated in Tm：LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuouswave maximum output power of 0.67 W. The emission wavelengths of Tm：LSO laser are centred around 2.06μm with spectral bandwidth of -13.6 nm.     

Efficient Diode-Pumped Tm：YALO3 Laser with a Pump Recycling Scheme

By using a pump recycling configuration, the maximum power of 8.1 W in the wavelength range 1.935-1.938 μm is generated by a 5-ram long Tm：YAIOa （4 at.%） laser operating at 18℃ with a pump power of 24 W. The highest slope efficiency of 42% is attained, and the pump quantum efficiency is up to 100%. The Tm：YAlO3 laser is employed as a pumping source of singly-doped Ho（1%）：GdV04 laser operating at room temperature, in which continuous wave output power of greater than 0.2 W at 2.05/μm is achieved with a slope efficiency of 9%.     

室温下光纤耦合二极管泵浦Tm:YAP激光器

 为实现室温下小型化、高效率的1.9 mm激光输出,采用793.5 nm激光二极管泵浦Tm:YAP晶体，晶体采用热电制冷及风冷的方式控制在18 ℃，采用1∶1的聚焦耦系统，获得功率为2.2 W、中心波长为1 928 nm的激光输出，光光转换效率为31%，斜率效率达41%。对影响激光输出的耦合输出率、腔型、腔长、晶体工作温度等因素进行了实验分析，实验结果表明：输出功率的变化与温度基本成线性关系,当增加激光谐振腔长时，由于高阶模式损耗加大以及晶体热透镜效应的加重导致腔内损耗加大，输出功率和斜率效率都有所下降。     

不同掺杂浓度Ce:YAP闪烁晶体的性能研究

Ce：YAP晶体具有优良的闪烁性能，其主要特点是衰减时间短，光产额大，在高能射线探测、核医学等方面有着广阔的应用前景。考虑到Ce^3＋离子浓度可能对晶体性能的影响，用中频感应加热提拉法生长了系列掺杂浓度为0．05％～0．6％的Ce：YAP闪烁晶体，晶体尺寸为垂50mm×80mm。室温下测试了不同浓度Ce：YAP晶体的透过、荧光、X射线激发发射、X射线激发衰减等特征，分析了Ce^3＋离子浓度对Ce：YAP晶体的透过、荧光及闪烁性能的影响。结果表明：随着Ce^3＋离子浓度增加，Ce：YAP晶体的吸收边发生红移，造成了样品的自吸收，从而影响到Ce：YAP晶体的光输出；且随Ce^3＋离子浓度增加，Ce：YAP晶体的衰减时间减少。     

High efficient diode-pumped Tm:YAP laser at room temperature

A high efficient diode-pumped Tm:YAP laser is reported. The maximum output power at 1981 nm is 5.2 W and the slope efficiency is 30%. Unpolarized absorption near 800 nm and unpolarized fluorescence spectra near 1800 nm pumped by laser diode (LD) are measured. In addition, the relationship between operation temperature and output power is discussed.