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.
Wavefront sensors represent a powerful technique for quantitative phase measurement. This paper presents a single-phase continuous self-imaging grating (SPCSIG) for quadriwave lateral shearing interferometry with high measurement accuracy and high adaptability. The SPCSIG is characterized by a single-stage phase structure with the phase distribution in each period encoded by the macro pixel, which achieves an approximate complex amplitude transmittance. In the simulation, the SPCSIG far field stray light is significantly suppressed. The near field interferograms propagation is stable, and the residuals are close to the theoretical limit. The method is expected to be used in the future such as precision optical metrology, X-ray wavefront sensing, or polymer gratings where hybrid gratings are not suitable.
We proposed a self-referenced technique for measuring the spatiotemporal characteristics of ultrashort pulses using the coherent diffraction imaging. This technique includes the wavelength spatial multiplexing coherent diffraction imaging measurement and the three-dimensional spatiotemporal amplitude and phase reconstruction. In experiment, we verified the feasibility of this technique by measuring a pulse from the femtosecond laser oscillator. Wavelength spatial multiplexing was realized by the combination of two-dimensional diffracted optical element and narrow-band-pass filter, and the amplitude and phase information of each wavelength was recovered by ePIE (extended Ptychographic Iterative Engine) algorithm. This technique can measure the three-dimensional spatiotemporal amplitude and phase information of ultrashort pulses with high resolution and simplicity. In the future, it is expected to be an effective method for the comprehensive monitoring of the spatiotemporal optical field of ultrashort pulse lasers, and will be helpful for the laser performance improvement.
We proposed a single-shot diagnostic for spatiotemporal laser-plasma evolution by the multi-dimensional encoding (MuDE) holography. It can achieves high and adjustable temporal resolution measurement of three-dimensional plasma distribution without delay scanning. Experimentally, we verified the feasibility of this technique, and the retrieved results of laser-plasma evolution agreed well with the direct shadow measurement. This technique is expected to provide a helpful tool for the complex spatiotemporal evolution of plasma in ICF and high energy density physics.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.