【作者】 袁伟； 邢昕； 韩冬佳； 李泽汉； 薛冰； 小林孝嘉； 杜鹃； 赵元安； 冷雨欣； 邵建达；

【Author】 Wei Yuan;Xin Xing;Dongjia Han;Zehan Li;Bing Xue;Takayoshi Kobayashi;Juan Du;Yuanan Zhao;Yuxin Leng;Jianda Shao;State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences;Key Laboratory of Materials for High Power Laser,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences;Advanced Ultrafast Laser Research Center,University of Electro-Communications;

【机构】 强场激光物理国家重点实验室,中国科学院上海光学精密机械研究所； 中科院强激光材料重点实验室,中国科学院上海光学精密机械研究所； 先端超高速激光研究中心,日本电气通信大学；

【摘要】 利用紫外飞秒激光器研究了Al₂O₃/SiO₂高反射膜内的超快载流子动力学。通过激光光谱实验,发现该反射膜Al₂O₃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。通过紫外光飞秒激光与光学薄膜作用后,观察到了反射率随时间的下降。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,该模型说明了电子从导带向缺陷态的弛豫,通过该理论模型得出的激光损伤阈值数据和实验数据吻合得很好。更多还原

【Abstract】 Ultrafast carrier dynamics in Al₂O₃/SiO₂ high reflectors has been investigated by UV femtosecond laser. It is identified by laser spectroscopy that, the carrier dynamics contributed from the front few layers of Al₂O₃ play a dominating role in the initial laser-induced damage of the UV reflector. Timeresolved reflection decrease after the UV excitation is observed, and conduction electrons is found to relaxed to a mid-gap defect state locating about one photon below the conduction band. To interpret the laser inducedcarrier dynamics further, a theoretical model including electrons relaxation to a mid-gap state is built, and agrees very well with the experimental results. To the best of our knowledge, this is the first study on the predamage dynamics in UV high reflector induced by femtosecond UV laser.更多还原