Time Delay Distribution and Laser Stability in Arbitrary Detuning Asynchronous Optical Sampling

TL;DR

This paper analyzes the performance and artifacts in ADA-SOPS, an advanced optical sampling technique, providing a theoretical model validated by experiments and introducing an algorithm for energy fluctuation compensation.

Contribution

It offers a detailed theoretical analysis of measurement performance in ADA-SOPS and introduces a new algorithm to automatically compensate energy fluctuations.

Findings

Delays are correlated with the interval between amplified pulses.

Artifacts can be mitigated with specific compensation strategies.

The new algorithm improves measurement stability by compensating energy fluctuations.

Abstract

Arbitrary Detuning ASynchronous OPtical Sampling (ADA-SOPS) is an emerging technique for extending standard pump--probe experiments performed with two femtosecond lasers to multitimescale experiments, which are of great interest for the study of complex systems. Although no specific requirements are needed for laser repetition rates, their ratio determines the achievable delay distribution and therefore is strongly related to the temporal resolution of the technique. We report a detailed theoretical analysis of measurement performances with respect to laser repetition rates, and we validate our model with experimental data. In the case of amplified laser systems, we demonstrate that achieved delays are inherently correlated to the time interval between amplified pulses, which affects the pulse energy and can generate artifacts. Nevertheless, a deep understanding of the origin of such artifacts allows to suggest several compensation strategies, either during data analysis or at the conception of the experimental setup. Finally we present a new algorithm integrated into the ADASOPS device: by selecting pairs of probe pulses having the same elapsed time with respect to the previous pulse, it automatically compensates any effect of energy fluctuation.