Spectrally modulated Stokes polarimeters use a pair of high-order crystal retarders to generate a spectrally dependent modulation of the polarization of light. In these systems, the detected intensity versus wavenumber spectrum is usually referred to as a channeled spectrum, and the Fourier inversion of this spectrum allows the determination of Stokes parameters of light without needing any other mechanical or active device for polarization control. This work proposes a spectrally modulated polarimeter beyond the concept of a channeled wavenumber spectrum, so effectively detaching the spectral modulation from the Fourier analysis technique. The wavelength domain analysis we use is best suited for dispersive spectrometers offering intensity versus wavelength measurements. The technique is illustrated with the measurement of very small optical rotations produced by sucrose solutions. The proposed technique is easily extendable to spectrally modulated Mueller polarimeters.
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http://dx.doi.org/10.1364/AO.456608 | DOI Listing |
J Med Imaging (Bellingham)
January 2025
U.S. Food and Drug Administration, Office of Science and Engineering Labs, Division of Imaging, Diagnostics, and Software Reliability, Silver Spring, Maryland, United States.
Purpose: We evaluate the impact of charge summing correction on a cadmium telluride (CdTe)-based photon-counting detector in breast computed tomography (CT).
Approach: We employ a custom-built laboratory benchtop system using the X-THOR FX30 0.75-mm CdTe detector (Varex Imaging, Salt Lake City, Utah, United States) with a pixel pitch of 0.
Handb Clin Neurol
January 2025
Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland; Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland.
The nonvisual effects of light in humans are mainly conveyed by a subset of retinal ganglion cells that contain the pigment melanopsin which renders them intrinsically photosensitive (= intrinsically photosensitive retinal ganglion cells, ipRGCs). They have direct connections to the main circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus and modulate a variety of physiological processes, pineal melatonin secretion, autonomic functions, cognitive processes such as attention, and behavior, including sleep and wakefulness. This is because efferent projections from the SCN reach other hypothalamic nuclei, the pineal gland, thalamus, basal forebrain, and the brainstem.
View Article and Find Full Text PDFEur J Pharmacol
January 2025
Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
Buspirone, a commonly prescribed medication for generalized anxiety disorder (GAD), is gaining attention for its narrow window of side effects such as lack of physical dependence, non-sedative properties as compared to other anxiolytic drugs. Its dose-specific therapeutic effects beyond anxiety highlights its clinical significance. Pharmacologically, buspirone activates serotonin-1A pre-synaptic autoreceptors and post-synaptic heteroreceptors which modulate serotonergic neurotransmission induced behavioral changes such as anxiolytic and nootropic effects.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
We present direct frequency comb cavity ring-down spectroscopy with Vernier filtering as a straightforward approach to sensitive and multiplexed trace gas detection. The high finesse cavity acts both to extend the interaction length with the sample and as a spectral filter, alleviating the need for dispersive elements or an interferometer. In this demonstration, a free running interband cascade laser was used to generate a comb centered at 3.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Wuhan National Laboratory for Optoelectronics, Next Generation Internet Access National Engineering Laboratory, and Hubei Optics Valley Laboratory, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China.
We propose and validate a novel optical semantic transmission scheme using multimode fiber (MMF). By leveraging the frequency sensitivity of intermodal dispersion in MMFs, we achieve high-dimensional semantic encoding and decoding in the frequency domain. Our system maps symbols to 128 distinct frequencies spaced at 600 kHz intervals, demonstrating a seven-fold increase in capacity compared to conventional communication encoding.
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