Cross-phase modulation in the two dimensional spectroscopy

TL;DR

This paper investigates cross-phase modulation effects in two-dimensional pump-probe spectroscopy, demonstrating how pulse interference causes spectral distortions and how pulse chirp compression can mitigate these effects.

Contribution

It extends understanding of XPM phenomena from transient absorption to 2D spectroscopy and offers strategies to reduce spectral distortions caused by pulse interference.

Findings

XPM causes oscillatory spectral distortions in 2D spectra.

Interference of pump pulses induces XPM in 2D spectroscopy.

Compressing probe pulse chirp reduces XPM impact.

Abstract

Developing from the transient absorption (TA) spectroscopy, the two dimensional (2D) spectroscopy with pump-probe geometry has emerged as a versatile approach for alleviating the difficulty on implementing the 2D spectroscopy with other geometries. However, the presence of cross-phase modulation (XPM) in TA spectroscopy introduces significant spectral distortions, particularly when the pump and probe pulses overlap. We demonstrate that this phenomenon is extended to the 2D spectroscopy with pump-probe geometry and the XPM is induced by the interference of the two pump pulse. We present the oscillatory behavior of XPM in the 2D spectrum and its displacement with respect to the waiting time delay through both experimental measurements and numerical simulations. Additionally, we explore the influence of probe pulse chirp on XPM and discover that by compressing the chirp, the impact of XPM on the desired signal can be reduced.