Single-shot ultrafast multidimensional optical imaging (UMOI) combines ultrahigh temporal resolution with multidimensional imaging capabilities in a snapshot, making it an essential tool for real-time detection and analysis of ultrafast scenes. However, current single-shot UMOI techniques cannot simultaneously capture the spatial-temporal-spectral complex amplitude information, hampering it from complete analyses of ultrafast scenes. To address this issue, we propose a single-shot spatial-temporal-spectral complex amplitude imaging (STS-CAI) technique using wavelength and time multiplexing. By employing precise modulation of a broadband pulse via an encoding plate in coherent diffraction imaging and spatial-temporal shearing through a wide-open-slit streak camera, dual-mode multiplexing image reconstruction of wavelength and time is achieved, which significantly enhances the efficiency of information acquisition. Experimentally, a custom-built STS-CAI apparatus precisely measures the spatiotemporal characteristics of picosecond spatiotemporally chirped and spatial vortex pulses, respectively. STS-CAI demonstrates both ultrahigh temporal resolution and robust phase sensitivity. Prospectively, this technique is valuable for spatiotemporal coupling measurements of large-aperture ultrashort pulses and offers promising applications in both fundamental research and applied sciences.

Optical Engineering (OE) publishes peer-reviewed papers reporting on research, development, and applications of optics, photonics, and imaging science and engineering.

A half-trace retrieval algorithm based on an extended-ptychographical iterative engine algorithm is proposed to reconstruct the temporal structure of pulse from a polluted and recorded frequency-resolved optical gating (FROG) trace that was modulated by poor spatial profile of output pulses, stray light, or misalignment of the measurement setup. In the proposed algorithm, the probe pulse and the gated pulse were retrieved simultaneously from a recorded FROG trace with a half-delay range, and the measured pulse was obtained by combining the different edges of the probe pulse and the gated pulse. Numerical simulations were carried out to verify the feasibility of the proposed algorithm. A single-shot picoseconds (ps)−THG−FROG setup with a 100$-\mathsf{\mu }$J ps laser system and an online ps−SHG−FROG setup in PW laser system were built to test the proposed algorithm experimentally. The results show that the temporal structure of pulses retrieved by the half-trace retrieval algorithm is closer to the real temporal structure than that retrieved by the conventional ptychographical algorithm when the recorded FROG trace is badly polluted.

提出一种时域剪切干涉技术测量纳秒激光脉冲的时间相位分布, 该方法将待测脉冲分为彼此之间有数百个皮秒延迟量的两个脉冲; 并在对其中一个脉冲加入适量的频移后和另一个脉冲合束, 得到时域干涉条纹; 最后采用相适应的算法, 从记录的时域条纹计算得到纳秒激光脉冲的时间相位分布, 并进一步计算得到激光脉冲的精细光谱结构. 在对测量原理进行系统分析的基础上, 利用数值模拟和实验对该相位测量技术的可行性进行了验证, 并系统分析了其测量误差和非理想条件下的各种干扰因素的影响. 由于该测量技术不采用任何非线光学方法, 可对任何波长的激光脉冲进行测量, 具有光路简单、测量精度高和适用范围广等优点, 为需要对纳秒激光脉冲的时域相位分布进行测量的高功率激光等领域提供了一种简单便捷的测量新技术.

A Babinet-principle-based coherent amplitude modulation imaging (BP-CAMI) method is proposed for accurate illumination characterization. It employs a random amplitude plate and a complementary constraint derived from the Babinet principle, establishing a dual-constraint framework that provides algorithmic rather than hardware redundancy. This approach effectively suppresses noise and artifacts during phase retrieval. Simulations and experiments on biomedical samples, resolution targets, and phase objects confirm substantial improvements in signal-to-noise ratio and spatial accuracy over conventional methods. Notably, BP-CAMI recovers richer high-frequency details than the ptychographic iterative engine, with quantitative gains of 2.85 dB PSNR and 7.81 μm resolvable linewidth, yet requires no hardware modifications. The work offers a practical, algorithm-driven route to enhance performance across coded-imaging systems.