Photothermal Spectroscopy Methods
Photothermal Spectroscopy Methods Thermal lens spectroscopy (TLS) is one of a family of photothermal techniques that can be used for physical and chemical analysis and is well suited for the characterization of transparent materials. An improvement in the limits of optical absorption detection of three orders of magnitude or more than that obtained by conventional absorbance spectrophotometric techniques has been achieved, which is ideal for ultra-trace determination and absorption spectrum measurements. By using TLS, absolute fluorescent quantum yields can be deduced precisely without the requirement for luminescent standards. TLS has also been employed for the measurements of thermal properties such as thermal diffusivity of solid and liquid samples. In the thermal lens measurement, a transparent sample is illuminated using radiation from a laser beam (excitation beam) Some of the radiation is absorbed by the sample or by chromophores within the sample. Excited-state species