Self-referencing ultrafast wide-field pump-probe microscopy.

Abstract

Ultrafast pump-probe microscopy reveals spatial heterogeneity in material properties including charge and energy transfer, electron-phonon coupling, and vibrational dynamics. At high spatial resolution, weak nonlinear signals often require point scanning with significant signal averaging, limiting studies of non-repeatable processes or systems prone to photodamage from prolonged laser exposure. To overcome these limitations, we introduce a wide-field pump-probe approach that integrates Parallel Rapid Imaging with Spectroscopic Mapping (PRISM) and a self-referencing method, suppressing noise by more than two orders of magnitude. Our technique exploits spatial correlations within the field of view to denoise and suppress laser intensity fluctuations without a reference detector, enabling acquisition of over one million pump-probe traces in under a second. This capability supports high-throughput material screening, real-time ultrafast spectroscopy, and investigations of non-reversible dynamics. Applied to few-layer WSe₂ and monolayer WSe₂/MoSe₂ heterostructures, the method resolves vibrational modes and substrate-induced coupling previously hidden by laser noise.