Widefield temporal shearing pump-probe microscopy with a common-path, dispersion free interferometer

Pump-probe microscopy involves the measurement of small changes in an electromagnetic field’s amplitude and phase, often in the presence of large backgrounds. Typically, this is achieved by measuring the difference between probe beam intensities with and without a pump beam. We demonstrate optical subtraction of probe and reference fields with a novel common path interferometer. This allows for intrinsic sensitivity to transient phase signals. For transient amplitude signals, signal to background ratio is enhanced. Uniquely, this interferometer demonstrates negligible phase and group delay dispersion with angle of incidence, allowing convenient widefield imaging.