• Current Optics and Photonics
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• v.6 no.2
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• pp.171-182
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• 2022

A single-photon laser and mid-wave infrared (MWIR) common aperture optical system was designed and developed to detect and range a long-distance civil aviation aircraft. The secondary mirror of the Ritchey-Chretien (R-C) optical system was chosen as a dichroic lens to realize the design of a common aperture system for the laser and MWIR. Point spread function (PSF) ellipticity was introduced to evaluate the coupling efficiency of the laser receiving system. A small aperture stop and narrow filter were set in the secondary image plane and an afocal light path of the laser system, respectively, and the stray light suppression ability of the small aperture stop was verified by modeling and simulation. With high-precision manufacturing technology by single point diamond turning (SPDT) and a high-efficiency dichroic coating, the laser/MWIR common aperture optical system with a 𝜑300 mm aluminum alloy mirror obtained images of buildings at a distance of 5 km with great quality. A civil aviation aircraft detection experiment was conducted. The results show that the common aperture system could detect and track long-distance civil aviation aircraft effectively, and the coverage was more than 450 km (signal-to-noise ratio = 6.3). It satisfied the application requirements for earlier warning and ranging of long-range targets in the area of aviation, aerospace and ground detection systems.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.65-69
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• 2008

Purpose: To develop a dot sight device for a sighting shot using the doublet reflector. Methods: We designed the singlet reflector and the doublet reflector by Sigma 2000 program and compared the one to the other. Results: In analysis of finite ray aberration, we could confirm that it has the effective field of view with the free-parallax which is 3.3 times wider than the existing dot sight device using the singlet reflector. If you use the doublet reflector, the central thickness of optical system become more than two times bigger than the existing one. As a result, when the image of a target object is made on the observer's retina, if you make the first side's radius of curvature equal with the second one as the case of the singlet reflector, changes in magnification are appeared. To conquer this problem, we had to make be satisfied with the afocal condition in the case of doublet reflector. Conclusions: we could develop the dot sight device for a sighting shot using the doublet reflector which has the effective field of view with the free-parallax which is 3.3 times wider than the existing dot sight device using the singlet reflector.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.58.1-58.1
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• 2017

The NISS (Near-infrared Imaging Spectrometer for Star formation history) is the near-infrared spectro-photometric instrument optimized to the first Next Generation of small satellite (NEXTSat-1). The off-axis optics was developed to cover a wide field of view with 2 deg. ${\times}$ 2 deg. as well as a wide wavelength range from 0.95 to $2.5{\mu}m$. Considering the simple alignment scheme, afocal system was adapted in the optical components. The mechanical structures were tested under the space environment. We have obtained the accurate calibration data using our test facilities under the operational condition. After the final integration of flight model into the satellite, the communication with the satellite and the functional test were passed. The NISS will be launched in early 2018. During around 2-year operation, the spectro-photometric survey covering more than 100 square degree will be performed. To achieve the major scientific objectives for the study of the cosmic star formation in local and distant universe, the main observational targets will be nearby galaxies, galaxy clusters, star-forming regions and low background regions. Here, we report the final performance of the flight model of the NISS.