A lidar system based on the coherent detection of oppositely chirped pulses generated using a 20 MHz mode locked laser and chirped fiber Bragg gratings is presented. Sub millimeter resolution ranging is performed with > 25 dB signal to noise ratio. Simultaneous, range and Doppler velocity measurements are experimentally demonstrated using a target moving at > 330 km/h inside the laboratory.
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http://dx.doi.org/10.1364/OE.19.011213 | DOI Listing |
We propose a method for controlling the time-varying polarization of optical pulses by introducing a quarter-wave plate into a 4-f pulse shaper and using a spatial light modulator to impose a group delay. This setup enables the polarization state of the incident pulse to vary over time. Specifically, for linearly chirped incident pulses, the polarization ellipse twists uniformly over time, while its ellipticity changes monotonically.
View Article and Find Full Text PDFJ Assoc Res Otolaryngol
October 2024
Aix Marseille Univ, CNRS, Centrale Marseille, LMA UMR 7031, 13013, Marseille, France.
Introduction: Although a broadband acoustic click is physically the shortest duration sound we can hear, its peripheral neural representation is not as short because of cochlear filtering. The traveling wave imposes frequency-dependent delays to the sound waveform so that in response to a click, apical nerve fibers, coding for low frequencies, are excited several milliseconds after basal fibers, coding for high frequencies. Nevertheless, a click sounds like a click and these across-fiber delays are not perceived.
View Article and Find Full Text PDFMeasurement resolution and dynamic range of conventional optical fiber sensors are often mutually restricted. In this work, an in-fiber chirped Fabry-Perot cavity (interferometer) is proposed, for the first time to our knowledge, to resolve the conflict between the resolution and dynamic range. The chirped Fabry-Perot interferometer is constructed by two chirped fiber Bragg gratings inscribed in the opposite directions, resulting in a gradually varied (i.
View Article and Find Full Text PDFChemphyschem
June 2024
Department of Chemistry "G. Ciamician", University of Bologna, Via F. Selmi 2, 40126, Bologna, Italy.
The chirped-pulse Fourier Transform microwave spectrum of 2-tert-butylphenol, an industrial intermediate for the production of antioxidants, has been investigated in the 2-8 GHz frequency range. The spectral analysis has allowed obtaining precise structural information on the most stable conformer and its complex with argon. The conformation of the monomer reveals that the hydroxyl group is coplanar with the ring but points in the opposite direction to the tert-butyl group, reducing steric interactions.
View Article and Find Full Text PDFJ Cancer
January 2024
Department of Thoracic Surgery, Fujian Medical University Union Hospital, Fuzhou, Fujian, 350001, China.
This study aimed to elucidate the underlying mechanism of LncRNA PRKCA-AS1 in lung adenocarcinoma (LUAD). The expression of LncRNA PRKCA-AS1, miR-508-5p and S100A16, in LUAD tissues or cell lines (NCI-H520 and H1299) was analyzed with qRT-PCR. The clinical diagnostic value of LncRNA PRKCAAS1, miR-508-5p and S100A16 in LUAD were analyzed by receptor operating characteristic (ROC) curve.
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