Short-pulse-induced thermal lensing effect in 1,2-dichloroethane and 1,2-dibromoethane

Abstract

1,2-dichloroethane () and 1,2-dibromoethane () show linear absorption (LA) and stimulated light scattering in response to the excitation by 820 nm 18 fs laser pulses. Using the -scan technique, with these pulses separated by 12.2 ns (much shorter than both samples’ thermal diffusivity time constants ’s) and extended over 41 ms (considerably longer than ’s), we investigated the thermal lensing effect of both samples and found that LA dominates their heating. In addition, relative to , shows more/less thermal lensing effect before/after the exposure time passes ’s. This means that the thermal lensing effect is more severely reinforced by heating and stabilized by thermal diffusivity in than in . Notably, the Kerr lensing effect is negligible in this study, although it is noticeable in a -scan study with 17 ps laser pulses.