Ta_(2)O_(5) films are deposited on fused silica substrates by electron beam evaporation method.The optical property,x-ray photoelectron spectroscopy,band gap and nanosecond laser-induced damage threshold(LIDT)of the f...Ta_(2)O_(5) films are deposited on fused silica substrates by electron beam evaporation method.The optical property,x-ray photoelectron spectroscopy,band gap and nanosecond laser-induced damage threshold(LIDT)of the films before and after annealing are studied.It is found that the existence of an oxygen vacancy results in the decrease of the transmittance,refractive index,both macroscopic band gap and microscopic band gap,and the LIDT of Ta_(2)O_(5) films.If the oxygen vacancy forms,the macroscopic band gap decreases 2%.However,when the oxygen vacancy forms the microscopic band gap decreases 73%for crystalline Ta_(2)O_(5) and 77%for amorphous Ta_(2)O_(5).The serious decrease of microscopic band gap may significantly increase the absorbance of the micro-area in Ta_(2)O_(5) films when irradiated by laser,thus the damage probability increases.It is consistent with our experimental results that the LIDT of the as-deposited Ta_(2)O_(5) films is 7.3 J/cm^(2),which increases 26%to 9.2 J/cm^(2) when the oxygen vacancy is eliminated after annealing.展开更多
基金Supported by the National Natural Science Foundation of China(Nos 61107080,50921002)the Natural Science Foundation of Jiangsu Province of China(No BK2011223)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(New Teachers)(No 20110095120018)the China Postdoctoral Science Foundation(No 20110491472)the National Undergraduate Innovation Experiment Programs(No 2012106)the Fundamental Research Funds for the Central Universities(No 2012QNA03).
文摘Ta_(2)O_(5) films are deposited on fused silica substrates by electron beam evaporation method.The optical property,x-ray photoelectron spectroscopy,band gap and nanosecond laser-induced damage threshold(LIDT)of the films before and after annealing are studied.It is found that the existence of an oxygen vacancy results in the decrease of the transmittance,refractive index,both macroscopic band gap and microscopic band gap,and the LIDT of Ta_(2)O_(5) films.If the oxygen vacancy forms,the macroscopic band gap decreases 2%.However,when the oxygen vacancy forms the microscopic band gap decreases 73%for crystalline Ta_(2)O_(5) and 77%for amorphous Ta_(2)O_(5).The serious decrease of microscopic band gap may significantly increase the absorbance of the micro-area in Ta_(2)O_(5) films when irradiated by laser,thus the damage probability increases.It is consistent with our experimental results that the LIDT of the as-deposited Ta_(2)O_(5) films is 7.3 J/cm^(2),which increases 26%to 9.2 J/cm^(2) when the oxygen vacancy is eliminated after annealing.
