Ultrafast single-shot imaging of femtosecond pulse propagation in transparent liquids using a supercontinuum and optical polarigraphy

We investigated the ultrafast time-resolved single-shot imaging of femtosecond pulse propagation using a supercontinuum and optical polarigraphy in transparent liquids. The probe supercontinuum senses the instantaneous birefringence induced by the laser pulse, and a polarigraphy image with different color distributions could be obtained. By comparing the wavelength distributions and the saturation variation of the images, the recorded polarigraphy images in two samples with different response time were analyzed. In the fast response sample, N-methyl-2-pyrrolidone (NMP), the spectral widths and the saturation values of the polarigraphy image at fixed positions were narrower and higher than those in CS₂. Due to the slow response of CS₂, the probe light sensed a long-lived birefringence and the polarigraphy image contained more wavelength components at every position along the pump pulse propagation direction.