深圳大学物理与光电工程学院,广东 深圳 518060
在现有单次测量极高速成像方法中,直接成像方法的分辨率高但探测系统复杂,而计算成像方法探测系统简单但易损失空间分辨率。因此,提出一种基于偏振编码的极高速成像技术。所提成像系统利用半波片阵列和偏振片阵列对入射飞秒脉冲、出射飞秒脉冲和动态事件进行偏振编码,并通过线性方程组解码极高速动态的时序图像。通过构建光学模型并仿真,精确还原了多幅图像,验证了所提方案的可行性,理论摄影频率在1013 frame/s以上,本征空间分辨率可达114 lp/mm。所提成像系统结合了直接成像和计算成像系统的优势:线性方程组精确求解,不会导致光学系统分辨率损失;时序图像叠加使探测结构只需分光不需要对不同时刻的图像进行空间上的分离,简化了探测器的结构。该极高速成像系统的时间分辨率仅受脉冲宽度限制,可以实现飞秒级动态事件的探测,并且随着脉冲宽度的缩短,其时间分辨率可以得到进一步提升。
成像系统 偏振编码 极高速成像 线性方程组 时序图像 飞秒脉冲 光学学报
2022, 42(20): 2011002
Author Affiliations
Abstract
1 Shenzhen University, College of Physics and Optoelectronic Engineering, Shenzhen Key Lab of Micro-Nano Photonic Information Technology, Shenzhen, China
2 Shenzhen University, College of Electronic Information Engineering, Shenzhen, China
3 Institut National de la Recherche Scientifique, Centre Énergie Matériaux Télécommunications, Laboratory of Applied Computational Imaging, Varennes, Québec, Canada
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.
ultrafast imaging spatiotemporal resolution frame rate noncollinear optical parametric amplification Advanced Photonics
2020, 2(5): 056002
Author Affiliations
Abstract
1 Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, College of Physics and Optoelectronics Engineering, Shenzhen University, Shenzhen518060, China
2 College of Electronic and Information Engineering, Shenzhen University, Shenzhen518060, China
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.
noncollinear optical-parametric amplification rotating rate ultrafast frame imager ultrafast intensity-rotating optical field High Power Laser Science and Engineering
2020, 8(1): 010000e3
为达到高分辨率以及像面照度要求,大口径非球面反射镜在空间红外系统中被广泛使用。设计了针对口径 550 mm、F/1.2非球面的补偿器,基于三级像差理论分析计算了补偿器的初始结构参数。利用 ZEMAX软件对补偿器进行了优化设计,最终所得补偿器的设计结果满足非球面检验要求。对补偿器结构参数进行了灵敏度及公差分析,结果表明该补偿器可用于实际加工检验。
几何光学 三级像差理论 零位检验 非球面 geometric optics third-order aberration theory null compensation aspheric surface
Author Affiliations
Abstract
1 Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China
2 International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
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.
electric-field reconstruction shearing interferometry spectral phase ultrashort laser pulse High Power Laser Science and Engineering
2019, 7(1): 01000e13
Author Affiliations
Abstract
1 Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China
2 SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China
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.
Far infrared or terahertz Ultrafast measurements Electro-optical devices Spectroscopy, terahertz Interferometry Photonics Research
2018, 6(3): 03000177
深圳大学电子科学与技术学院深圳市微纳光子信息技术重点实验室, 广东 深圳 518060
针对现有的360°三维测量系统结构复杂、标定要求高、测量时间长等问题, 提出了一种结构简单、测量速度快的单传感器360°三维测量系统和一种操作方便、精度较高的标定方法。该系统由条纹投影系统、摄像机、两个前表面反射镜组成。测量时, 物体点云数据由三部分组成, 前表面通过摄像机获取, 对应于所拍图片的中间区域, 左右两面分别由左右两块前表面反射的平面镜获取, 分别对应图片的左右两区域。先对不含反射镜的系统进行标定, 然后加入两套反射镜, 利用透过式投影屏完成对左右两套系统的二次标定, 获得全局坐标系下的物体三维数据。实验表明, 该系统搭建成本较低, 标定精度较高, 重建速度快, 适合现场标定。
测量 三维测量 结构光 标定