Interferometric characterization of ultrashort deep ultraviolet pulses using a multiphoton ionization mass spectrometer

Abstract

The temporal characterization of a femtosecond laser pulse in the deep ultraviolet region using an interferometric autocorrelation scheme is demonstrated. Two-photon ionization of a molecule in a time-of-flight mass spectrometer was used as a nonlinear detector to obtain an autocorrelation trace. This setup proved useful in not only providing a temporal characterization of a pulse but also investigating the ultrafast dynamics of photochemical processes.

In situ third-order interferometric autocorrelation of a femtosecond deep-ultraviolet pulse

“…In the following FRAC measurement, NO [16] and Xe were simulta- Fig. 4(a) is consistent with the theoretically predicted shape of the FTL pulse shown in Fig.…”

“…This implies that Xe isotopes can provide a third-order nonlinear response over a wide spectral range (204 -306 nm) and would be useful for measuring the temporal profiles of ultrashort optical pulses by avoiding these two resonance wavelengths in the DUV region. The secondorder nonlinear response measured using NO as a nonlinear medium for multiphoton ionization has already been reported elsewhere [16]. An ionization energy that is lower for NO (9.26 eV) than for Xe, and the high energy level of the first excited singlet state (4.13 eV), limits the bandwidth for a second-order nonlinear response.…”

“…A MS is most effective for measuring ultrashort optical pulses in the wavelength region shorter than visible, where the dispersion due to the medium is more significant than in the visible and NIR regions. This technique is based on the multi-photon ionization (MPI) of a gaseous medium having no absorption band in the ultraviolet (UV) region [14][15][16][17]. The nphoton ionization generally yields a nonlinear signal proportional to the n-th order of the input pulse intensity.…”

A Simple Method for the Evaluation of the Pulse Width of an Ultraviolet Femtosecond Laser Used in Two-Photon Ionization Mass Spectrometry

“…For simple on-site measurement of pulse widths, a device based on fringe-resolved autocorrelation (FRAC) was developed, which consisted of an interferometer and a time-of-flight mass spectrometer that was used as a two-photon-response detector to measure a non-resonant two-photon ionization signal [18][19][20][21]. However, the laser beam must be split into two parts and recombined after the interferometer, which reduces the laser pulse energy and then the sensitivity of the mass spectrometer.…”

Autocorrelation and Frequency-Resolved Optical Gating Measurements Based on the Third Harmonic Generation in a Gaseous Medium

“…A GaN diode with a nature of two-photon absorption in the VIS region (at round 400 nm) has been employed as a detector in a fringe-resolved autocorrelator (FRAC) [7]. In a previous study, we reported on the development of an FRAC, in which a mass spectrometer was employed as a two-photon-response device in the DUV region (at around 267 nm) [8]. However, the frequency domain of these techniques is limited to one octave [9].…”