Ultrafast laser pre-damage dynamics process in Al2O3/SiO2high reflectors

利用紫外飞秒激光光谱技术研究了Al_2O_3/SiO_2高反射膜内的超快载流子动力学。通过实验,发现该反射膜Al_2O_3层的载流子动力学在紫外反射膜的激光诱导损伤中起着至关重要的作用。通过泵浦-探测实验,发现紫外飞秒激光与光学薄膜作用后,光学薄膜反射率有所下降,且探测光反射率变化的峰值在约2.3 ps的时间内从417 nm左右转移到402 nm左右。为了更好的解释激光诱导载流子动力学,一个具体的理论模型被提出来,该模型指出导带自由电子弛豫过程中与晶格相互作用,产生距导带一个光子能量的中间缺陷态,其初始电国家自然科学基金(61475169;61521093;11127901)A ring cavity Tm-doped fiber laser system was built based on a 1 550 nm fiber laser. And, its spectral chacteristics were investigated. With 1 550 nm pump, the spontaneous emission of the 1.6 m long Tm-doped fiber covered a spectral range from 1 800-1900 nm with a 3 dB bandwidth bigger than 60 nm. Inserting an isolator into the ring cavity, narrow linewidth output was obtained with a 3 dB linewidth smaller than 0.2 nm centering at around 1 900 nm. Further adding a tunable FP filter, tunable, narrow linewidth laser output was attained. The laser spectrum was tunable from 1 840 -1 900 nm with a broad tunable range reaching 60 nm while maintaining a 3 dB linewidth of only 0.07 nm. In addition, a telecommunication FP filter at the 1 550 nm waveband was also exploited in this ring cavity laser system for wavelength tuning. And, a narrow linewidth, broadband tunable laser output in two seperated spectral ranges was also recorded. Together with the 2000nm FP laser system, this laser demonstrates a wide tunable range from 1820-1915nm which is consistent with the spontaneous emission spectrum of the Tm-doped fiber. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved