现有极高速成像系统存在元件复杂、系统庞大以及视场受限的问题。基于螳螂虾小眼和复眼结构提出一种结构紧凑的极高速成像方法，可应用于多种视场和时间范围。仿生极高速成像仿生微绒毛阵列结构，以条纹结构光照明和空间角分复用为基础，实现图像的压缩和瞬态事件时序图像的重现。仿生螳螂虾小眼结构，可以实现视场极高速成像；而复眼系统结构上有小眼系统拼接组成，可以突破限制现大视场极高速成像。时间延迟结构与照明成像光路分离，可以实现飞秒至皮秒时间尺度的瞬态事件记录。因此，仿生多视场极高速成像理论上可以应用于各种视场的成像，仿真实验的摄影频率可以达到1.2×10¹³ 帧/s，还原图像分辨率可以达到80.6 lp/mm。仿生极高速成像为大范围、群体性瞬态事件的探测提供了可能，例如光在散射介质中的传播、随机运动等，并且其结构紧凑，为极高速成像仪器的小型化、轻量化打下基础。

Applying an ultrafast vortex laser as the pump, optical parametric amplification can be used for spiral phase-contrast imaging with high gain, wide spatial bandwidth, and high imaging contrast. Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues (frog egg cells and onion epidermis) with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright- or dark-field imaging under a weak illumination of 7nW/cm2. This work provides a powerful way for biological tissue imaging in the second near-infrared region.

This paper presents a novel design for single-shot terahertz polarization detection based on terahertz time-domain spectroscopy (THz-TDS). Its validity has been confirmed by comparing its detection results with those of the THz common-path spectral interferometer through two separate measurements for the orthogonal components. Our results also show that its detection signal-to-noise ratios (SNRs) are obviously superior to those of the 45° optical bias THz-TDS by electro-optical sampling due to its operation on common-path spectral interference rather than the polarization-sensitive intensity modulation. The setup works without need of any optical scan, which does not only save time, but also efficiently avoids the disturbances from the fluctuations of the system and environment. Its single-shot mode allows it to work well for the applications with poor or no repeatability.

We report a framing imaging based on noncollinear optical parametric amplification (NCOPA), named FINCOPA, which applies NCOPA for the first time to single-shot ultrafast optical imaging. In an experiment targeting a laser-induced air plasma grating, FINCOPA achieved 50 fs-resolved optical imaging with a spatial resolution of ～83 lp / mm and an effective frame rate of 10 trillion frames per second (Tfps). It has also successfully visualized an ultrafast rotating optical field with an effective frame rate of 15 Tfps. FINCOPA has simultaneously a femtosecond-level temporal resolution and frame interval and a micrometer-level spatial resolution. Combining outstanding spatial and temporal resolutions with an ultrahigh frame rate, FINCOPA will contribute to high-spatiotemporal resolution observations of ultrafast transient events, such as atomic or molecular dynamics in photonic materials, plasma physics, and laser inertial-confinement fusion.

A tunable ultrafast intensity-rotating optical field is generated by overlapping a pair of 20 Hz, 800 nm chirped pulses with a Michelson interferometer (MI). Its rotating rate can be up to 10 trillion radians per second ($\text{Trad}/\text{s}$), which can be flexibly tuned with a mirror in the MI. Besides, its fold rotational symmetry structure is also changeable by controlling the difference from the topological charges of the pulse pair. Experimentally, we have successfully developed a two-petal lattice with a tunable rotating speed from $3.9~\text{Trad}/\text{s}$ up to $11.9~\text{Trad}/\text{s}$, which is confirmed by our single-shot ultrafast frame imager based on noncollinear optical-parametric amplification with its highest frame rate of 15 trillion frames per second (Tfps). This work is carried out at a low repetition rate. Therefore, it can be applied at relativistic, even ultrarelativistic, intensities, which usually operate in low repetition rate ultrashort and ultraintense laser systems. We believe that it may have application in laser-plasma-based accelerators, strong terahertz radiations and celestial phenomena.

This paper presents a complete two-step phase-shifting (TSPS) spectral phase interferometry for direct electric-field reconstruction (SPIDER) to improve the reconstruction of ultrafast optical fields. Here, complete TSPS acts as a balanced detection that can not only remove the effect of the dc term of the interferogram, but also reduce measurement noises, and thereby improve the capability of SPIDER to measure the pulses with narrow spectra or complex spectral structures. Some prisms are chosen to replace some environment-sensitive optical components, especially reflective optics to improve operating stability and improve signal-to-noise ratio further. Our experiments show that the available shear can be decreased to 1.5% of the spectral width, which is only about $1/3$ compared with traditional SPIDER.

This paper reports the experimental realization of efficiently sorting vector beams by polarization topological charge (PTC). The PTC of a vector beam can be defined as the repetition number of polarization state change along the azimuthal axis, while its sign stands for the rotating direction of the polarization. Here, a couple of liquid crystal Pancharatnam–Berry optical elements (PBOEs) have been used to introduce conjugated spatial phase modulations for two orthogonal circular polarization states. Applying these PBOEs in a 4-f optical system, our experiments show the setup can work for PTC sorting with a separation efficiency of more than 58%. This work provides an effective way to decode information from different PTCs, which may be interesting in many fields, especially in optical communication.

To seek high signal-to-noise ratio (SNR) is critical but challenging for single-shot intense terahertz (THz) coherent detection. This paper presents an improved common-path spectral interferometer for single-shot THz detection with a single chirped pulse as the probe for THz electro-optic (EO) sampling. Here, the spectral interference occurs between the two orthogonal polarization components with a required relative time delay generated with only a birefringent plate after the EO sensor. Our experiments show that this interferometer can effectively suppress the noise usually suffered in a non-common-path interferometer. The measured single-shot SNR is up to 88.85, and the measured THz waveforms are independent of the orientation of the used ZnTe EO sensor, so it is easy to operate and the results are more reliable. These features mean that the interferometer is quite qualified for applications where strong THz pulses, usually with single-shot or low repetition rate, are indispensable.