强脉冲激光激发的热透镜光度分析法

Thermal Lens Spectrophotometry Based on Strong Pulsed Laser Excitation

用自装的热透镜测量装置,观察了强脉冲激光作用下的热透镜行为。测量丙酮/水混合液中的Cocl_(2),检测限为3×10^(-7)M,相当于6×10^(-6)的吸光度。将差分放大技术用于热透镜测量,降低了He-Ne激光振幅噪声的影响,改善了信噪比。

The thermal lens effects based on the strong pulsed laser excitation were observed by using the home-made experimental apparatus.In acetone-water mixture concentrations of CoCl2as low as 3×10^(-7)M have been determined with present setup,which corresponds to an absorbance of 6×10^(-6).In thermal lens measurements the noise level due to shot-term instability of the He-Ne laser output amplitude can be reduced down by the use of differential amplification technique,thus the S/N ratio is improved appreciably.