Experimental demonstration on 400†nm-scale bandwidth optical parametric chirped-pulse amplification based on mixed cascaded crystals.

We present an optical parametric chirped-pulse amplification (OPCPA) based on mixed cascaded crystals, taking advantage of the unique parametric phase-matching of lithium triborate (LiB3O5, LBO) and yttrium calcium oxyborate ((YCa4O(BO3)3, YCOB) crystals. The OPCPA properties of LBO at 880 nm and YCOB at 750 nm are studied respectively. After amplification by two LBO and two YCOB crystals, a total signal gain of 108 and spectral bandwidth close to 400 nm is obtained. After accurate dispersion compensation with a grating-pair compressor and chirped mirror compensator, a pulse duration of 9.4 fs is obtained by a SHG-frequency-resolved optical grating (FROG). This approach will be of great significance in high energy amplifier for high peak power few-cycle laser sources.

Simple single-shot complete spatiotemporal intensity and phase measurement of an arbitrary ultrashort pulse using coherent modulation imaging.

We propose a simple single-shot spatiotemporal measurement technique called coherent modulation imaging for the spatio-spectrum (CMISS), which reconstructs the full three-dimensional high-resolution characteristics of ultrashort pulses based on frequency-space division and coherent modulation imaging. We demonstrated it experimentally by measuring the spatiotemporal amplitude and phase of a single pulse with a spatial resolution of 44 µm and a phase accuracy of 0.04 rad. CMISS has good potential for high-power ultrashort-pulse laser facilities and can measure even spatiotemporally complicated pulses with important applications.

Universal nanosecond range pulse contrast measurement for a kJ-class petawatt laser.

A single-shot measuring apparatus with optical limiting for temporal pulse contrast of kJ-class petawatt lasers in the nanosecond range is proposed. A temporal linear filter comprising an electro-optical switch, a polarizer, a temporal nonlinear filter composed of cascaded SHG crystals, and a dichromatic mirror are, respectively, used as an optical limiting apparatus for contrast measurement of nanosecond and picosecond pulses to improve dynamic range and temporal resolution. The apparatus has been applied to pulse contrast measurements at the SG-II petawatt facility, achieving a high dynamic range of 1010 and a fast time resolution of 107 ps in the 350 ns range. This technique can also be universally applied to the limiting of the main pulse of varying pulse widths to diagnose pre-pulses during generation and transmission.