We present a micro star tracker with curved vanes that offers a short length of the baffle and a sharp cutoff of stray light. The curved vanes are derived mathematically by ray-tracing in such a way that all the stray light from outside of the desired field of view (FOV) is reflected out. The proposed curved vane design allows a smaller number of vanes to completely cut off stray light, leading to a shorter length in baffle design. Furthermore, the capability of a sharp cutoff of stray light eases the sensitivity requirement of image sensors. For the experiment, we fabricated three micro star tracker baffles with curved vanes for 22° FOV, which are required to handle a maximum star magnitude of 5.35 for 100% sky coverage. The sizes of the baffles fabricated are 16×16.5 L with double curved vanes, 24×12.1 L with a single curved vane, and 27×14.4 L with double curved vanes. In comparison, the straight vane baffle designed for 22° FOV requires seven vanes with 18 mm length but results only in mild stray light attenuation with the cutoff at 32°. The proposed star tracker utilizes a 5-megapixel image sensor, 16×16×39 in size and weighing 9.2 g with an accuracy of 1.288 arcsecond, a 20.6% improvement over when no baffle is used.
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http://dx.doi.org/10.1364/AO.380774 | DOI Listing |
Mater Horiz
December 2024
Quantum Materials and Devices Unit, Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali 140306, India.
The 'pyro-phototronic effect' plays a nontrivial role in advancing ferroelectric (FE) devices of light detectors, light-emitting diodes, and other smart technologies. In this work, a premier FE copolymer, poly(vinylidene fluoride--trifluoro ethylene) (P(VDF-TrFE)), is reinforced with a lead-free double perovskite, CsSnI, to render profound properties in a hybrid nanostructure. It presents a unique example of the coupling of ferro-, pyro- and piezo-electrics to the 'photoexcitation' of exotic charges that actively empower the synergetic features.
View Article and Find Full Text PDFAiming at the problem of overbrightness of the target simulator background for LED backlight panel illumination, a 5° aperture angle-matched collimated illumination method for the target simulator is proposed based on the study of the dark-state leakage of the LCD display device and the scattered stray light of the system. After simulation analysis the method can make the display contrast increase by 3.1 times and solve the problem of dark targets being drowned by the background bright light, which exists in the LED illumination target simulator.
View Article and Find Full Text PDFSensors (Basel)
November 2024
MOE Key Laboratory of Fundamental Physical Quantities Measurement and Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
Under the influence of the polarization effect, the background stray light of the weak starlight simulator and the polarization state of the simulated target star point are doped with each other, so it is difficult to achieve accurate suppression of polarized stray light. In this paper, the mechanism of background stray light induced by the optical engine in a weak starlight simulation device is analyzed, and the principle of mutual doping between stray light and simulated target starlight polarization state is studied. The correlation model of polarization parameters, point source transmittal, and simulated target magnitude was established, and the optimization process of polarization effect was constructed to achieve accurate suppression of polarized stray light in the star map background.
View Article and Find Full Text PDFThe geostationary orbit imaging spectrometer offers distinct advantages for diverse applications in remote sensing. To enhance swath and data richness, there is a growing trend toward spectrometers with broader fields of view (FOV) and extended slit lengths. Optical systems equipped with these features face significant challenges in aberration correction.
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