Non-iterative characterization of few-cycle laser pulses using flat-top gates

Abstract

We demonstrate a method for broadband laser pulse characterization based on a spectrally resolved cross-correlation with a narrowband flat-top gate pulse. Excellent phase-matching by collinear excitation in a microscope focus is exploited by degenerate four-wave mixing in a microscope slide. Direct group delay extraction of an octave spanning spectrum which is generated in a highly nonlinear fiber allows for spectral phase retrieval. The validity of the technique is supported by the comparison with an independent second-harmonic fringe-resolved autocorrelation measurement for an 11 fs laser pulse.

Graphene Near-Degenerate Four-Wave Mixing for Phase Characterization of Broadband Pulses in Ultrafast Microscopy

“…In this case, the procedure could be modified, for example, the spectrum could be compressed stepwise by limiting the bandwidth. We also note that other pulse characterization procedures based on FWM have been presented, for example, in combination with an additional gate pulse 33 or spectral detection analogous to FROG. 34 Compared to these procedures, the presented approach based on graphene's near-degenerate four-wave mixing appears to be simpler and more easily implemented.…”

Removing non-resonant background from broadband CARS using a physics-informed neural network

“…We propose two methods to obtain S and E pr with relative advantages/disadvantages. The first method involves cross-correlation frequency resolved optical gating (XFROG), as described by Selm 20 which returns the electric fields E S and E pr from which S can be calculated exactly.…”

Temporally flat top pulse generation from gain switched semiconductor lasers based on a polarization interferometer with variable transfer function

“…This is the case of flat top pulses which are employed in a large variety of applications, e.g. retiming of high data bit rate optical communication channels in C band [2], efficient pumping of free electron lasers in the deep Ultra Violet wavelength region [3] and amplitude and phase characterization of ultra-short pulses [4], Common methods for flat top pulse generation are based on spectral filtering of Gaussian, transform limited, ultra-short pulses obtained from mode locked lasers [5]. The general approach is based on pulse spectral filtering by means of a specifically designed photonic device, adapted to the intensity and phase profiles of the seed pulse.…”