In this paper we design a high-performance multispectral telescope with a concave elliptical grating for a field of view of 3° in the VNIR spectral range of 0.48-0.82 µm, at an altitude of 760 km from the ground, with total length of 140 mm, which has a small volume and a simple structure. The paper reports on the MTF, spot, and field curvature diagrams, which show that it can achieve spectral and spatial resolutions of 25 nm and 5.5 m, respectively, with good image quality (MTF value for all wavelengths is higher than 0.2 at Nyquist frequency of 217 cycles per mm) and has the least possible aberrations, without the need for any lenses.
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http://dx.doi.org/10.1364/AO.502424 | DOI Listing |
In this paper we design a high-performance multispectral telescope with a concave elliptical grating for a field of view of 3° in the VNIR spectral range of 0.48-0.82 µm, at an altitude of 760 km from the ground, with total length of 140 mm, which has a small volume and a simple structure.
View Article and Find Full Text PDFAny high-contrast imaging instrument in a future large space-based telescope will include an integral field spectrograph (IFS) for measuring broadband starlight residuals and characterizing the exoplanet's atmospheric spectrum. In this paper, we report the development of a high-contrast integral field spectrograph (HCIFS) at Princeton University and demonstrate its application in multi-spectral wavefront control. Moreover, we propose and experimentally validate a new reduced-dimensional system identification algorithm for an IFS imaging system, which improves the system's wavefront control speed, contrast and computational and data storage efficiency.
View Article and Find Full Text PDFSensors (Basel)
February 2018
Department of Aerospace Engineering, Tohoku University, Aramaki Aza Aoba 6-6-11, Sendai 980-8579, Japan.
Although nano/microsatellites have great potential as remote sensing platforms, the spatial and spectral resolutions of an optical payload instrument are limited. In this study, a high spatial resolution multispectral sensor, the High-Precision Telescope (HPT), was developed for the RISING-2 microsatellite. The HPT has four image sensors: three in the visible region of the spectrum used for the composition of true color images, and a fourth in the near-infrared region, which employs liquid crystal tunable filter (LCTF) technology for wavelength scanning.
View Article and Find Full Text PDFSensors (Basel)
March 2016
CSIRO Land & Water, GPO Box 1666, Canberra, ACT 2601, Australia.
Radiometric calibration of the Dual-Wavelength Echidna(®) Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρ(app)), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρ(app) are 8.1% for 1064 nm and 6.
View Article and Find Full Text PDFThe passive imaging polarimeter architecture is based on optical coatings and thereby avoids the complexities of current systems that use rotating polarizers, phase-modulating retarders, and birefringent elements. Coatings on stationary elements separate spectral regions and their polarized components to simultaneously produce images of the Stokes linear polarization intensities in fields of view (FOVs) ≥30°. Wavelength and FOV coverages are limited only by the telescope and relay optics employed.
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