Stray light
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Derivation and validation of the stray light correction algorithm for the thermal infrared sensor onboard Landsat 8 Open
It has been known and documented that the Thermal Infrared Sensor (TIRS) on-board Landsat 8 suffers from a significant stray light problem (Reuter et al., 2015; Montanaro et al., 2014a). The issue appears both as a non-uniform banding arti…
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Fluorescence Imaging Spectrometer (FLORIS) for ESA FLEX Mission Open
The Fluorescence Explorer (FLEX) mission has been selected as ESA’s 8th Earth Explorer mission. The primary objectives of the mission are to provide global estimates of vegetation fluorescence, actual photosynthetic activity, and vegetatio…
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Step-by-step guide to reduce spatial coherence of laser light using a rotating ground glass diffuser Open
Wide field-of-view imaging of fast processes in a microscope requires high light intensities motivating the use of lasers as light sources. However, due to their long spatial coherence length, lasers are inappropriate for such applications…
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A Case of Letting the Cat out of The Bag—Why Trap-Neuter-Return Is Not an Ethical Solution for Stray Cat (Felis catus) Management Open
Trap-Neuter-Return (TNR) programs, in which stray cats are captured, neutered and returned to the environment are advocated as a humane, ethical alternative to euthanasia. We review the TNR literature in light of current debate over whethe…
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Improving visible light OCT of the human retina with rapid spectral shaping and axial tracking Open
Visible light optical coherence tomography (OCT) theoretically provides finer axial resolution than near-infrared OCT for a given wavelength bandwidth. To realize this potential in the human retina in vivo, the unique technical challenges …
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Spatial-Light-Modulator-Based Multichannel Data Transmission by Vortex Beams of Various Orders Open
We report an atmospheric multichannel data transmission system with channel separation by vortex beams of various orders, including half-integer values. For the demultiplexing of the communication channels, a multichannel diffractive optic…
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Calibration and evaluation of CCD spectroradiometers for ground-based and airborne measurements of spectral actinic flux densities Open
The properties and performance of charge-coupled device (CCD) array spectroradiometers for the measurement of atmospheric spectral actinic flux densities (280–650 nm) and photolysis frequencies were investigated. These instruments are wide…
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Design of an optical see-through light-field near-eye display using a discrete lenslet array Open
In this paper, we propose a novel method to construct an optical see-through light-field near-eye display (OST LF-NED) by using a discrete lenslet array (DLA). The DLA is used as a spatial light modulator (SLM) to generate dense light fiel…
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Optical design and evaluation of airborne prism-grating imaging spectrometer Open
We have focused on the optical form that is low cost while maintaining high performance for airborne application. We report the optical design as well as the alignment and test results for a push-broom imaging spectrometer. The smart archi…
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Astrometric Calibration and Performance of the Dark Energy Camera Open
In this study, we characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500 Mpix, 3-deg2 science field of view and across four years of operation. This is done using internal comparisons of ~4…
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Nanopatterned luminescent concentrators for visible light communications Open
Visible light communication (VLC) is a promising candidate for high-speed wireless communication with numerous unlicensed spectrum. To achieve high-speed data communication, it requires intense light signals concentrated on a tiny fast pho…
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Fourier DiffuserScope: single-shot 3D Fourier light field microscopy with a diffuser Open
Light field microscopy (LFM) uses a microlens array (MLA) near the sensor plane of a microscope to achieve single-shot 3D imaging of a sample without any moving parts. Unfortunately, the 3D capability of LFM comes with a significant loss o…
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Ultrabroadband 2D electronic spectroscopy with high-speed, shot-to-shot detection Open
Two-dimensional electronic spectroscopy (2DES) is an incisive tool for disentangling excited state energies and dynamics in the condensed phase by directly mapping out the correlation between excitation and emission frequencies as a functi…
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Ppb-level detection of ammonia based on QEPAS using a power amplified laser and a low resonance frequency quartz tuning fork Open
In this report, an ultra-high sensitive quartz-enhanced photoacoustic spectroscopy (QEPAS) based ammonia (NH3) sensor using a power amplified diode laser and a low resonance frequency quartz tuning fork (QTF) was demonstrated for the first…
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Quality assessment of solar UV irradiance measured with array spectroradiometers Open
The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends i…
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High-NA open-top selective-plane illumination microscopy for biological imaging Open
Selective-plane illumination microscopy (SPIM) provides unparalleled advantages for the volumetric imaging of living organisms over extended times. However, the spatial configuration of a SPIM system often limits its compatibility with man…
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The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II Open
A technology center for the production of high-precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at-wavelength characterization of UV- and XUV-reflection grating…
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NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 2—design, manufacturing, and testing of the ultraviolet and visible channel Open
NOMAD is a spectrometer suite on board the ESA/Roscosmos ExoMars Trace Gas Orbiter, which launched in March 2016. NOMAD consists of two infrared channels and one ultraviolet and visible channel, allowing the instrument to perform observati…
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Optical design, laboratory test, and calibration of airborne long wave infrared imaging spectrometer Open
We discuss and evaluate a long wave infrared imaging spectrometer in terms of its opto-mechanical design and analysis, alignment, testing, and calibration. The instrument is a practical airborne sensor achieving high spectral resolution an…
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Multifield direct design method for ultrashort throw ratio projection optics with two tailored mirrors Open
In this work, we present a multifield direct design method for ultrashort throw ratio projection optics. The multifield design method allows us to directly calculate two freeform mirror profiles, which are fitted by odd polynomials and imp…
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Rapid optimization method of the strong stray light elimination for extremely weak light signal detection Open
The strong stray light has huge interference on the detection of weak and small optical signals, and is difficult to suppress. In this paper, a miniaturized baffle with angled vanes was proposed and a rapid optimization model of strong lig…
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Fiber-Amplifier-Enhanced QEPAS Sensor for Simultaneous Trace Gas Detection of NH3 and H2S Open
A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS) sensor, employing an erbium-doped fiber amplifier (EDFA), and a distributed feedback (DFB) laser operating at 1582 nm was demonstrated for simultaneous detection …
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Highly efficient blazed grating with multilayer coating for tender X-ray energies Open
For photon energies of 1 - 5 keV, blazed gratings with multilayer coating are ideally suited for the suppression of stray and higher orders light in grating monochromators. We developed and characterized a blazed 2000 lines/mm grating coat…
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Optical system design of star sensor and stray light analysis Open
Background: Star sensor is one of the precise attitude determination sensors. It is an electro-optical system that takes an image from a set of stars and by comparing it with the star catalogue determines angle deviation of the satellite a…
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Twin-beam sub-shot-noise raster-scanning microscope Open
By exploiting the quantised nature of light, we demonstrate a sub-shot-noise scanning optical transmittance microscope. Our microscope demonstrates, with micron scale resolution, a factor of improvement in precision of 1.76(9) in transmitt…
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Compact near-eye display system using a superlens-based microlens array magnifier Open
A new type of very compact optical element for a near-eye display (NED) that uses a pair of microlens arrays (MLAs) is presented. The MLA pair works in conjunction to form a magnifier (collimator). The purpose of this is to aid in the acco…
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Broadband near-infrared astronomical spectrometer calibration and on-sky validation with an electro-optic laser frequency comb Open
The quest for extrasolar planets and their characterization as well as studies of fundamental physics on cosmological scales rely on capabilities of high-resolution astronomical spectroscopy. A central requirement is a precise wavelength c…
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Open-path cavity ring-down spectroscopy for trace gas measurements in ambient air Open
The present work used a near-infrared methane cavity ring-down spectroscopy (CRDS) sensor to examine performance and limitations of open-path CRDS for atmospheric measurements. A simple purge-enclosure was developed to maintain high mirror…
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How Dark the Sky: The JWST Backgrounds Open
We describe the sources of stray light and thermal background that affect JWST observations, report actual backgrounds as measured from commissioning and early-science observations, compare these background levels to prelaunch predictions,…
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PSF model for diffractive optical elements with improved imaging performance in dual-waveband infrared systems Open
Single-layer diffractive optical elements (SLDOEs) have advantages in terms of configuration, fabrication, range of angles and cost; however, the diffraction efficiency decreases sharply with wavelength deviating from the design wavelength…