Ultrafast wide-field 3D topography with extended depth of field

TL;DR

This paper introduces an ultrafast, wide-field 3D topography imaging system with extended depth of field, high spatial and temporal resolution, enabling real-time 3D measurements without axial scanning.

Contribution

It presents a novel pump-probe interferometric microscope that significantly extends depth of field while maintaining high resolution, allowing single-frame 3D imaging in dynamic scenarios.

Findings

Captured axial material flow during laser-induced microsphere melting.

Tracked azimuthal rotation of ablation lobes during optical vortex propagation.

Demonstrated real-time 3D topography reconstruction without axial scanning.

Abstract

Ultrafast optical imaging has enabled direct observation of femtosecond-nanosecond dynamics, yet three-dimensional (3D) dynamic measurements at high numerical aperture (NA) remain hindered by the intrinsically shallow depth of field (DoF) of conventional microscopes. Here, we propose an ultrafast, wide-field pump-probe interferometric microscope on a telecentric platform that significantly extends the effective DoF to ~18 micrometer at a high NA of 0.9 while maintaining high spatial resolution (down to 235 nm) and temporal resolution (~170 fs). The system enables single-frame 3D topography reconstruction without axial scanning or multi-view acquisition. We demonstrate these capabilities by capturing axial material flow during laser-induced microsphere melting that remain unobservable with conventional narrow-DoF systems, and by tracking the azimuthal rotation of ablation lobes during axial propagation of temporal focused spatiotemporal optical vortex (TF-STOV) pulses, directly revealing the spatiotemporal evolution of STOV-matter interactions