Mode-mismatched thermal lens experiment in the pulse regime

摘要

We present a pump-probe mode-mismatched thermal lens method for pulse excitation aimed to the measurement of one- and multi-photon absorption coefficient with high sensitivity. Short pulses of light are used as pump source while the probe field is a collimated CW light of low power. The method is used for the measurement of absorption of distilled water and ethanol. Absorption coefficient as small as 10~(-8) cm~(-1) can be measured with the described technique.