宋奇林 1,2,3,4李杨 1,3,4周子夜 1,3,4肖亚维 1,2,3,4[ ... ]饶长辉 1,2,3,4
1 自适应光学全国重点实验室,四川 成都 610209
2 中国科学院大学,北京 100049
3 中国科学院光电技术研究所,四川 成都 610209
4 中国科学院自适应光学重点实验室,四川 成都 610209
Overview: Since the groundbreaking discovery of gravitational waves, the scientific community has fervently pursued the exploration of low-frequency gravitational waves to glean deeper insights into the cosmos. The inherent limitations of ground-based conditions, however, pose formidable challenges for detectors in capturing gravitational waves below the 1 Hz threshold. Consequently, the imperative has shifted toward the deployment of space-based gravitational wave detectors as the paramount solution for effective low-frequency gravitational wave detection. At the crux of space-based gravitational wave detection lies the pivotal role of spaceborne telescopes. Given the expansive transmission distances spanning magnitudes of 109 m between celestial constellations, the demand for nanoradian-level precision in telescope pointing accuracy becomes non-negotiable. The concomitant necessity for high-precision measurements and calibration emerges as a prerequisite for achieving the exacting standards of pointing accuracy in spaceborne telescopes dedicated to gravitational wave detection. To ameliorate the deleterious effects of pointing deviations on gravitational wave detection, this study strategically optimizes key parameters, including microlens structures, detector selection, and algorithmic frameworks, thereby achieving a breakthrough in high-precision pointing deviation measurements. Leveraging a low-density microlens array with extended sub-aperture focal lengths enhances the spatial scale of the light spot within each sub-aperture. This, coupled with detectors boasting a high signal-to-noise ratio, synergistically elevates the pointing detection accuracy of each discrete lens. Moreover, the paper introduces an innovative, Hartmann principle-based methodology for high-precision pointing deviation measurements, deploying a spatially reused paradigm across multiple sub-apertures. By aggregating measurement results from diverse sub-apertures, the approach effectively mitigates the influence of assorted random errors on measurement accuracy, thereby markedly enhancing the precision of pointing deviation measurements. Illustrating the efficacy of these methodologies, the paper exemplifies their application within the ambit of the "Tianqin Plan" for space-based gravitational wave detection. Employing numerical simulations and factoring in the design parameters of the Hartmann sensor, the study performs a meticulous analysis of pointing deviation measurement accuracy. Comparative analysis between single sub-aperture and sub-aperture correlation reuse technologies reveals a compelling enhancement in measurement accuracy, approximating a sevenfold improvement with the latter. The pointing deviation measurement accuracy achieved through sub-aperture correlation reuse technology is quantified at approximately 18.81 nanoradians. Considering the optical magnification inherent in spaceborne telescopes, estimated at around 30 times, the resultant pointing deviation measurement accuracy reaches an impressive 0.62 nanoradians. This design precision significantly surpasses the stipulated 1 nanoradian accuracy requirement for ground-based gravitational wave pointing deviation measurements. As a prudential measure, the proposed design incorporates a substantial margin to accommodate potential accuracy diminution attributable to external perturbations during empirical testing.
星载望远镜 指向偏差测量 哈特曼 多子孔径空间复用 spaceborne telescope pointing deviation measurement Hartmann multi-subaperture spatial multiplexing
Author Affiliations
Abstract
1 Department of Engineering Physics, Tsinghua University, Beijing 100084, China
2 National Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi’an 710024, China
Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights into the generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of the pulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography 3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are often available for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete data may introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. We augment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have been carried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns between adjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstruction results and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.
Matter and Radiation at Extremes
2024, 9(2): 027801
1 五邑大学 智能制造学部, 广东 江门 529020
2 暨南大学 物理与光电工程学院, 广东 广州 510632
钙钛矿太阳能电池仅用十年左右的时间将效率提升至认证的26.1%,非常接近晶硅太阳能电池26.81%的认证效率,展现出巨大的产业化潜力。当前,钙钛矿太阳能电池器件效率还在提升,然而在器件制备过程中,钙钛矿太阳能电池的性能受到许多不可分割的因素影响,传统方法往往采用试错的方式来优化钙钛矿太阳能电池的制备工艺,花费了大量的时间。贝叶斯优化是一种全局优化算法,在解决人工智能的黑盒问题方面取得了很大的成功。本文利用贝叶斯优化算法对钙钛矿层涉及到的碘化铅(PbI2)过量百分比、退火温度、退火时间、真空萃取时间四个工艺参数进行优化选择,显著降低了研发成本,缩短了研发时间。通过五轮实验迭代,累计34组工艺条件,制备出了器件效率为23.56%的反型钙钛矿太阳能电池。
钙钛矿太阳能电池 机器学习 工艺优化 高效率 perovskite solar cells machine learning process optimization high efficiency
西南交通大学机械工程学院,四川 成都 610031
在对图像位移进行测量时,不同亚像素位移迭代算法的性能不同,将反向组合对角近似算法和反向组合Dog-Leg算法用于数字图像相关法并进行位移测量,同时对反向组合Levenberg-Marquardt算法的参数更新策略进行简化,以反向组合高斯牛顿(IC-GN)法作为对比,通过模拟散斑图像和真实散斑图像的压缩变形实验,对3种算法的性能进行对比,并进行相应的评估。实验结果表明:在模拟散斑实验中,各个算法在收敛速度、收敛频率和计算速度上各有不同;在真实实验下,小变形实验得到与IC-GN法相似的精度,大变形实验得到的收敛半径更大。
测量 数字图像相关法 亚像素位移 反向组合对角近似算法 反向组合Levenberg-Marquardt算法 反向组合Dog-Leg算法
1 广州医科大学生物医学工程学院,广东 广州 511436
2 宁波大学信息科学与工程学院光+X交叉科学与技术研究院,浙江 宁波 315211
近红外光源对生物组织具有穿透力强、无损检测、信噪比高等特点,广泛应用于成分检测、安防监控、生物医学等领域。但是目前缺乏高效率、便携化的近红外光源,这成为了限制智能检测技术发展的关键。与传统的近红外光源相比,荧光粉转换的近红外LED光源(NIR pc-LED)具有便携、高效的特点。本研究采用工艺简单、绿色环保的水热法合成了Li3Na3Ga2F12∶Cr3+近红外宽带荧光粉,并通过控制保温温度、保温时间等参数,确定了荧光材料的最佳合成方案,研究了氟化物颗粒尺寸、形貌演化,以及Cr3+掺杂浓度对Li3Na3Ga2F12∶Cr3+发光性能的影响。Li3Na3Ga2F12∶Cr3+材料能够实现630~980 nm范围宽带发射,半峰全宽(FWHM)为110 nm,峰值为766 nm,其内量子效率高达74%。结合商用蓝光LED,成功封装了近红外宽带LED光源,其在50 mA驱动电流下的近红外光输出功率是10.32 mW,光电转换效率达到5.1%。最后通过鸡胸肉下的静脉近红外成像以及夜视成像演示,验证了该近红外宽带LED光源在医疗以及食品检测等成像领域中的应用可行性。
绿色合成 宽带近红外发光 Li3Na3Ga2F12∶Cr3+ LED器件 激光与光电子学进展
2024, 61(3): 0316004