Pulse Retrieval Algorithm for Interferometric Frequency-Resolved Optical Gating Based on Differential Evolution

TL;DR

This paper introduces a differential evolution algorithm for interferometric FROG pulse retrieval, demonstrating improved robustness, accuracy, and noise resilience over standard methods through numerical and experimental validation.

Contribution

The novel algorithm leverages genetic optimization to enhance pulse retrieval accuracy and robustness in interferometric FROG measurements, outperforming existing methods.

Findings

Outperforms generalized projections algorithm in accuracy

Robust against experimental artifacts and noise

Validated with experimental data from Ti:sapphire laser

Abstract

A novel algorithm for the ultrashort laser pulse characterization method of interferometric frequency-resolved optical gating (iFROG) is presented. Based on a genetic method, namely differential evolution, the algorithm can exploit all available information of an iFROG measurement to retrieve the complex electric field of a pulse. The retrieval is subjected to a series of numerical tests to prove robustness of the algorithm against experimental artifacts and noise. These tests show that the integrated error-correction mechanisms of the iFROG method can be successfully used to remove the effect from timing errors and spectrally varying efficiency in the detection. Moreover, the accuracy and noise resilience of the new algorithm are shown to outperform retrieval based on the generalized projections algorithm, which is widely used as the standard method in FROG retrieval. The differential evolution algorithm is further validated with experimental data, measured with unamplified three-cycle pulses from a mode-locked Ti:sapphire laser. Additionally introducing group delay dispersion in the beam path, the retrieval results show excellent agreement with independent measurements with a commercial pulse measurement device based on spectral phase interferometry for direct electric-field retrieval. Further experimental tests with strongly attenuated pulses indicate resilience of differential evolution based retrieval against massive measurement noise.