Time-resolved imaging with OKE-based time-gate: enhancement in spatial resolution using low-coherence ultra-short illumination

TL;DR

This paper introduces a collinear OKE-based time-gate system utilizing low-coherence supercontinuum illumination to improve spatial resolution and reduce speckle artifacts in time-resolved imaging.

Contribution

It presents a novel low-coherence supercontinuum source for OKE-based time-gating, enhancing image quality by minimizing speckle artifacts compared to traditional coherent methods.

Findings

Reduced speckle artifacts in time-resolved images

Enhanced spatial resolution in imaging

Effective use of supercontinuum for time-gating

Abstract

We propose a collinear optical Kerr effect (OKE) based time-gate configuration with low coherence illumination source, derived from the supercontinuum (SC) generated by focusing the femtosecond laser pulses inside water. At first the spectral broadening in SC generation and corresponding changes in its coherence properties are studied and then a narrow band of wavelengths is extracted to use as the probe beam in the OKE-based time-gate configuration. The gate timings and spatial resolution of the time-gated images are also investigated. The low coherence of the probe ensures that the artifacts due to speckles from the laser are reduced to a minimum. To illustrate this a comparison of the time-resolved images of the fuel sprays obtained with this configuration has been made with the images obtained with the collinear, dual color configuration of the optical gate with coherent illumination.