飞秒激光在不同羟基浓度纯石英玻璃内部诱导缺陷研究

Femtosecond Laser Induced Defects in Pure Silica Glass with Different Hydroxyl Concentrations

采用飞秒激光脉冲辐照不同羟基浓度的纯石英玻璃,诱导其内部产生缺陷。系统研究了羟基浓度、激光脉宽和激光功率对缺陷类型和浓度的影响。石英玻璃的显微荧光谱、吸收谱和发射谱测试表明,飞秒激光诱导石英玻璃可以产生非桥氧空穴中心(NBOHC)、非弛豫氧空位[ODC(Ⅱ)]和E′心3种缺陷;低羟基浓度石英玻璃易产生ODC(Ⅱ)缺陷,高羟基浓度石英玻璃易产生NBOHC缺陷。用波长为254nm的紫外灯激发飞秒激光辐照后的高羟基浓度石英玻璃可观察到明显的红色荧光(波长为650nm),其发光强度与飞秒激光的脉宽和功率相关,发光强度随激光脉宽的增加先增加后减小,随激光功率的增加先增加后趋于平缓。

The internal defects are induced by irradiating pure silica glass with different hydroxyl concentrations by femtosecond laser pulses. Influences of hydroxyl concentration, laser pulse width and laser power on the type and concentration of defects are systematically investigated. The micro fluorescence spectra, absorption and emission spectra of silica glass show that the tested samples produce three kinds of defects including non-bridging oxygen hole center （NBOHC）, non-relaxation oxygen deficient center [ODC（Ⅱ）]and E′ center. ODC（Ⅱ） defect is easier to be induced when the hydroxyl concentration is lower, while NBOHC defect is easier to be induced when the hydroxyl concentration is higher. The obvious red fluorescence （650 nm） under ultraviolet lamp excitation （254 nm） in irradiated glass with high OH content can be observed. It is found that red fluorescence （650 nm） intensity closely depends on the laser pulse width and laser power, to be specific, it increases at first and then decreases with the increase of laser pulse width, and increases at first and then tends to slow with the increase of laser power.