Time-resolved image plane off-axis digital holography

In this work, we demonstrate off-axis image-plane digital holography for measuring ultrafast processes with high temporal resolution. The proposed image-plane holographic configuration in conjunction with numerical post-processing procedures allows us to neglect the walk-off effect in the off-axis arrangement by synthesizing spatial phase distribution with the whole field of view from separate fragments and to increase the spatial resolution by means of a telecentric system with adjustable magnification. We have analyzed temporal resolution taking into account all dispersing elements that increase the duration of the pulses being propagated through the optical setup. The technique was approved with experiment on measuring the dynamics of the refractive index, induced by laser filamentation in air.