Broadband spatiotemporal measurement using quadri-wave lateral shearing interferometry and compressed sensing: methods and parameter analysis

In high-power laser systems, ultra-short laser pulses commonly possess broad spectral bandwidths, leading to space-time coupling effects when interacting with optical elements, which can alter the quality of pulses. Traditional measurement techniques for characterizing these pulses often rely on time-consuming scanning methods or are restricted by limited spectral channels, making them unsuitable for broad-spectral, space-time measurements. To address these limitations, this paper introduces a model combining snapshot compressive imaging and quadri-wave lateral shearing for broad-spectral space-time measurements. Our analysis focuses on the effects of the number of channels, the number of code patterns, and the ratio of the interference points to coded pixel size on measurement accuracy. Utilizing the TWIST-TV algorithm and Fourier phase retrieval, we can reconstruct wavefront over a wide spectral range of 100 nm across 100 channels with RMSE of up to 0.012λ. The research establishes guidelines to maximize recovery accuracy, marking a substantial advancement in broad-spectral space-time field measurement technology.