Compact single-shot d-scan setup for the characterization of few-cycle laser pulses

Single-shot dispersion sampling for optical pulse reconstruction

We present a novel approach to single-shot characterization of the spectral phase of broadband laser pulses. Our method is inexpensive, insensitive to alignment and combines the simplicity and robustness of the dispersion scan technique, that does not require spatio-temporal pulse overlap, with the advantages of single-shot pulse characterization methods such as single-shot frequency-resolved optical gating at a real-time reconstruction rate of several Hz.

Transient-grating single-shot supercontinuum spectral interferometry (TG-SSSI)

We present a technique for the single-shot measurement of the spatiotemporal (1D space+time) amplitude and phase of an ultrashort laser pulse. The method, transient grating single-shot supercontinuum spectral interferometry (TG-SSSI), is demonstrated by the space-time imaging of short pulses carrying spatiotemporal optical vortices. TG-SSSI is well suited for characterizing ultrashort laser pulses that contain singularities associated with spin/orbital angular momentum or polarization.

Single-shot d-scan technique for ultrashort laser pulse characterization using transverse second-harmonic generation in random nonlinear crystals

We demonstrate a novel dispersion-scan (d-scan) scheme for single-shot temporal characterization of ultrashort laser pulses. The novelty of this method relies on the use of a highly dispersive crystal featuring antiparallel nonlinear domains with a random distribution and size. This crystal, capable of generating a transverse second-harmonic signal, acts simultaneously as the dispersive element and the nonlinear medium of the d-scan device. The resulting in-line architecture makes the technique very simple and robust, allowing the acquisition of single-shot d-scan traces in real time. The retrieved pulses are in very good agreement with independent frequency-resolved optical grating measurements. We also apply the new single-shot d-scan to a terawatt-class laser equipped with a programmable pulse shaper, obtaining an excellent agreement between the applied and the d-scan retrieved dispersions.

Rapid phase retrieval of ultrashort pulses from dispersion scan traces using deep neural networks

The knowledge of the temporal shape of femtosecond pulses is of major interest for all their applications. The reconstruction of the temporal shape of these pulses is an inverse problem for characterization techniques, which benefit from an inherent redundancy in the measurement. Conventionally, time-consuming optimization algorithms are used to solve the inverse problems. Here, we demonstrate the reconstruction of ultrashort pulses from dispersion scan traces employing a deep neural network. The network is trained with a multitude of artificial and noisy dispersion scan traces from randomly shaped pulses. The retrieval takes only 16 ms enabling video-rate reconstructions. This approach reveals a great tolerance against noisy conditions, delivering reliable retrievals from traces with signal-to-noise ratios down to 5.