Abstract

Thermal lensing spectrometry is used to measure low levels of absorption in a solution. When a solution is irradiated by a laser beam with a spatially Gaussian distribution, laser energy absorbed by the solute is converted to heat and transferred to the solvent. The resulting increase in solvent temperature causes a change in the refractive index of the solvent, which results in the formation of a lens in the part of the analytical solution that was irradiated by the laser. Generally, the samples measured by thermal lensing spectrometry are liquid. However, gases and solid crystals have also been observed.

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