Open AccessUltrafast pre-breakdown dynamics in Al_2O_3/SiO_2 reflector by femtosecond UV laser spectroscopy
Author(s) -
Jiangfeng Du,
Zehan Li,
Bing Xue,
Takayoshi Kobayashi,
Dongjia Han,
Yuanan Zhao,
Yuxin Leng
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.017653
Subject(s) - femtosecond , materials science , laser , optics , spectroscopy , ultrashort pulse , filamentation , electron , ultrafast laser spectroscopy , femtochemistry , optoelectronics , relaxation (psychology) , reflector (photography) , physics , light source , quantum mechanics , psychology , social psychology
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. Time-resolved 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 induced carrier 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 pre-damage dynamics in UV high reflector induced by femtosecond UV laser.