Characterization of weak deep ultraviolet pulses using cross-phase modulation scans

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.

Onset of Bloch oscillations in the almost-strong-field regime

“…2 b). As previous studies [22,23] revealed, the spectral fringes are produced by two DUV pulses that are well separated in time after the crystal. The leading pulse (labeled U) is in time with the Vis-IR pulse, whereas the trailing pulse (labeled V) propagates at the DUV group velocity [22][23][24].…”

“…As previous studies [22,23] revealed, the spectral fringes are produced by two DUV pulses that are well separated in time after the crystal. The leading pulse (labeled U) is in time with the Vis-IR pulse, whereas the trailing pulse (labeled V) propagates at the DUV group velocity [22][23][24]. V is beneficial for the interpretation of the data, because it is generated within the first few micrometers and maintains its spectrum in the subsequent linear propagation.…”

Harmonic Concatenation of 1.5 fs Pulses in the Deep Ultraviolet

“…For a further validation of the simulation results, the DUV waveforms are characterized with the recently developed method cross-phase modulation scans. 18 Spectra |E UV | 2 are recorded, while a further Vis-IR pulse, labeled R, is overlapped at a variable delay τ R , see Figure 1. The pulse characterization is performed both experimentally and on synthetic data, which is generated using the UPPE simulation, where all three pulses A, B, and R are initialized.…”

“…In order to scrutinize the mechanism of harmonic concatenation, simulations are employed similar as described in refs and − . The unidirectional pulse propagation equation (UPPE) is integrated numerically using the split-step method.…”

“…For a further validation of the simulation results, the DUV waveforms are characterized with the recently developed method cross-phase modulation scans . Spectra | E UV | 2 are recorded, while a further Vis-IR pulse, labeled R, is overlapped at a variable delay τ R , see Figure .…”