We demonstrate a high-speed photon-counting laser ranging system with laser pulses of multiple repetition rates to extend the unambiguous range. In the experiment, the laser pulses of three different repetition rates around 10 MHz were employed to enlarge the maximum unambiguous range from 15 m to 165 km. Moreover, the range of distances was increased as well, enabling the measurement on different targets of large separation distance with high depth resolution. An outdoor photon-counting laser ranging up to 21 km was realized with high repetition rate, which is beneficial for the airborne and satellite-based topographic mapping.
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http://dx.doi.org/10.1038/s41598-018-22675-1 | DOI Listing |
Natl Sci Rev
January 2025
Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.
The noise equivalent temperature difference (NETD) indicates the minimum temperature difference resolvable by using an infrared detector. The lower the NETD, the better the sensor can register small temperature differences. In this work, we proposed a strategy to achieve a high temperature resolution using a superconducting nanowire single-photon detector (SNSPD) with ultra-high sensitivity.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Advanced Membranes and Porous Materials Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
Understanding how structural modifications affect the photophysics of organic linkers is crucial for their integration into metal-organic frameworks (MOFs) for light-driven applications. This study explores the impact of varying the amine functional group position on two terephthalic acid derivatives─linker and linker ─by investigating their photophysics through a combination of steady-state and ultrafast laser spectroscopy and time-dependent density functional theory (TD-DFT) calculations. With tetrahydrofuran as the solvent, time-correlated single-photon counting revealed a 2-fold increase in the S excited-state lifetime of the molecule with the amine group at the meta position compared with that of the molecule with the amine group at the ortho position.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.
Time-resolved single molecule localization microscopy (TR-SMLM) with a 2 × 2 pixel fiber optic array camera was combined with time-correlated single photon counting (TCSPC) to obtain super-resolved fluorescence lifetime images of individual Cy3 dye molecules and individual colloidal CdSe/CdS/ZnS core/shell/shell semiconductor quantum dots (QDs). The characteristic blinking and bleaching behavior of the Cy3 and the blinking behavior of the QD emitters were used as distinguishing optical characteristics to isolate them and determine their centroid locations with spatial resolution below the optical diffraction limit. TCSPC was used to characterize the fluorescence lifetime and intensity corresponding to each emitter location.
View Article and Find Full Text PDFFluorescence interference is a pervasive challenge in Raman spectroscopy, often limiting its broader application. Time-gated Raman spectroscopy offers a more universal solution by temporally separating Raman signals from fluorescence; however, it faces significant challenges when dealing with samples that exhibit short fluorescence lifetimes. Achieving high time resolution to effectively distinguish these signals typically requires advanced detectors that are not only costly but also difficult to source commercially, often resulting in substantial residual fluorescence that diminishes overall signal quality.
View Article and Find Full Text PDFFluorescence lifetime imaging microscopy (FLIM) is a powerful technique for studying biological processes. There exists a growing interest in developing strategies to enhance throughput and reduce acquisition time of FLIM systems, which commonly employ laser scanning excitation and time-correlated single-photon counting (TCSPC) detection. In this work, we propose a wide-field FLIM microscope based on compressive sensing and high photon rate detection (beyond pile-up limit) based on a high-efficiency silicon photomultiplier detector as a single-pixel camera.
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