Beyond Intensity Modulation: New Approaches To Pump-Probe Microscopy

Pump-probe microscopy is an emerging nonlinear imaging technique based on high repetition rate lasers and fast intensity modulation. Here, we present new methods for pump-probe microscopy that keep the beam intensity constant and instead modulate the inter-pulse time delay or the relative polarization. These techniques can improve image quality for samples that have poor heat dissipation or long-lived radiative states and can selectively address nonlinear interactions in the sample. We experimentally demonstrate this approach and point out the advantages over conventional intensity modulation. (C) 2021 Optical Society of America