分类： 天文学 >> 天文仪器与技术 分类： 光学 >> 仪器仪表、测量和计量 分类： 光学 >> 相干和统计光学 提交时间： 2023-06-28
摘要： Co-phase and co-focus detection is one of the key technologies for large-aperture segmented mirror telescopes. In this paper, a new edge sensor based on fringes of equal thickness is developed, which can detect each segment's relative piston, tilt, and tip errors from the interferograms. Based on the co-focus demand for many ground-based seeing limited segmented mirror telescopes, an edge sensor prototype based on such a principle is built and applied in the indoor segmented mirror experiment system in the lab. According to the co-focus requirement of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, many simulations and experiments are carried out for co-focus error detection of the segmented mirror system. Experiment results show that the co-focus accuracy is better than 0.02 rms, which can meet the co-focus requirements of most large or extremely large segmented mirror astronomical telescopes.
分类： 光学 >> 量子光学 提交时间： 2023-06-25
摘要： 多光子纠缠是量子通讯、光量子计算的核心技术。现在普遍使用的纠缠光源是自发参量下转换产生的两光子纠缠，虽已取得很大的成就，但离量子计算等的应用需求还很远，需要从理论和实验两个方面探索新路。 本文研究了受激辐射射基础过程，受激辐射的机理，发现此过程最初产生的两光子态的量子性质与受激辐射物质的对称性密切相关。如果受激辐射物质的电子态有宇称，它的波函数也有宇称，如原子、有对称中心的分子、有反演对称的晶体等，这类物质的电子态都有宇称和反射对称性。有宇称的物质的受激辐射过程遵守宇称守恒，受激辐射产生的两光子态有宇称，是迭加纠缠态。这样的两个纠缠光子经过平行平面谐振腔的作用，再通过受激辐射，不断重复这个过程，最终产生多光子纠缠。 本文主要结果和结论是：有宇称的物质的受激辐射产生多光子纠缠态。激光器物质的电子态如有宇称，则激光器谐振腔内（平行平面腔）的受激辐射产生的多光子态是纠缠态，并可从对称结构的双向单模激光器输出。 理论给出多光子纠缠的表示式。研制成一台对称结构双向输出单模He-Ne激光器，进行了多光子纠缠态的实验验证，实验结果与理论预期相符。
分类： 核科学技术 >> 辐射物理与技术 分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 分类： 光学 >> 计算中的光学 分类： 核科学技术 >> 核科学技术其他学科 提交时间： 2023-06-08
摘要： Owing to the constraints on the fabrication of -ray coding plates with many pixels, few studies have been carried out on -ray computational ghost imaging. Thus, the development of coding plates with fewer pixels is essential to achieve -ray computational ghost imaging. Based on the regional similarity between Hadamard subcoding plates, this study presents an optimization method to reduce the number of pixels of Hadamard coding plates. First, a moving distance matrix was obtained to describe the regional similarity quantitatively. Second, based on the matrix, we used two ant colony optimization arrangement algorithms to maximize the reuse of pixels in the regional similarity area and obtain new compressed coding plates. With full sampling, these two algorithms improved the pixel utilization of the coding plate, and the compression ratio values were 54.2% and 58.9%, respectively. In addition, three undersampled sequences (the Harr, Russian dolls, and cake-cutting sequences) with different sampling rates were tested and discussed. With different sampling rates, our method reduced the number of pixels of all three sequences, especially for the Russian dolls and cake-cutting sequences. Therefore, our method can reduce the number of pixels, manufacturing cost, and difficulty of the coding plate, which is beneficial for the implementation and application of -ray computational ghost imaging.
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