Multi-frame Interferometric Imaging with a Femtosecond Stroboscopic Pulse Train for Observing Irreversible Phenomena

TL;DR

This paper introduces a femtosecond stroboscopic interferometric imaging technique capable of capturing multiple high-speed images in a single event, enabling detailed observation of rapid irreversible phenomena.

Contribution

The authors present a novel high-speed multi-frame interferometric imaging method using a femtosecond pulse train synchronized with a framing camera, allowing single-shot observation of fast irreversible events.

Findings

Successfully monitored laser-induced deformation in silicon nitride membranes.

Captured propagation of high-amplitude acoustic waves.

Applicable to observing phenomena like crack branching and dielectric breakdown.

Abstract

We describe a high-speed single-shot multi-frame interferometric imaging technique enabling multiple interferometric images with femtosecond exposure time over a 50 ns event window to be recorded following a single laser-induced excitation event. The stroboscopic illumination of a framing camera is made possible through the use of a doubling cavity which produces a femtosecond pulse train that is synchronized to the gated exposure windows of the individual frames of the camera. The imaging system utilizes a Michelson interferometer to extract phase and ultimately displacement information. We demonstrate the method by monitoring laser-induced deformation and the propagation of high-amplitude acoustic waves in a silicon nitride membrane. The method is applicable to a wide range of fast irreversible phenomena such as crack branching, shock-induced material damage, cavitation and dielectric breakdown.