# Interferometric Autocorrelation Measurements of Supercontinuum based on Two-Photon Absorption

## TL;DR

This paper demonstrates a simple, low-cost interferometric autocorrelation technique using two-photon absorption in GaP detectors to analyze the coherence properties of broadband supercontinuum light, distinguishing between coherent and incoherent regimes.

## Contribution

It introduces a novel interferometric autocorrelation method based on two-photon absorption for supercontinuum characterization, providing direct coherence measurements.

## Key findings

- Successfully measured coherence times and pulse durations of supercontinuum light.
- Differentiated between coherent and incoherent supercontinuum regimes.
- Showed the method's effectiveness in analyzing supercontinuum coherence properties.

## Abstract

We report on interferometric autocorrelation measurements of broadband supercontinuum light in the anomalous dispersion regime using two-photon absorption in a GaP photodetector. The method is simple, low-cost, and provides a direct measure of the second-order coherence properties, including quantitative information on the coherence time and average duration of the supercontinuum pulses as well as on the presence of temporally coherent sub-structures. We report measurements in regimes where the supercontinuum is coherent and incoherent. In the former case, the interferometric measurements are similar to what is observed for mode-locked laser pulses while in the latter case the interferometric measurements and coherence properties are shown to have characteristics similar to that of a stationary chaotic light source.