# Characterization of weak deep UV pulses using cross-phase modulation scans

## TL;DR

This paper introduces a novel, analytic method for characterizing weak deep UV laser pulses using cross-phase modulation scans, overcoming limitations of traditional techniques in the UV spectrum.

## Contribution

The method enables pulse characterization with picojoule-scale energies, specifically tailored for deep UV pulses, and provides a way to retrieve pulse information analytically with fidelity verification.

## Key findings

- Effective characterization of deep UV pulses with low energies
- Analytic pulse retrieval method demonstrated
- Fidelity of pulse reconstruction verified

## Abstract

Temporal pulse characterization methods can often not be applied to UV pulses due to the lack of suitable nonlinear crystals and very low pulse energies. Here, a method is introduced for the characterization of two unknown and independent laser pulses. The applicability is broad, but the method is especially useful for pulses in the deep UV, because pulse energies on the picojoule-scale suffice. The basis is a spectral analysis of the two interfering UV pulses, while one of the pulses is phase shifted by an unknown VIS-IR pulse via cross-phase modulation. The pulse retrieval is analytic and the fidelity can be checked by comparing the complex-valued data trace with the retrieved trace.