In a surprising finding, light can make water evaporate without heat

Nanowerk  November 2, 2023 Solar-driven evaporation rates using porous absorbers have been reported to exceed the theoretical thermal evaporation limit, but the mechanism of this phenomenon remains unclerogel materials was negligible. 2) Illumination of hydrogel under solar or visible-spectrum light-emitting diode led to evaporation rates exceeding the thermal evaporation limit, even in hydrogels without additional absorbers. 3) The evaporation rates were wavelength dependent, peaking at 520ar. Researchers at MIT found many unexpected results in their experiments: 1) Partially wetted hydrogels became absorbing in the visible spectral range, where the absorption by both the water and the hydrogel material is negligible. […]

Study reveals generation mechanism of radiative effects on novel active optical hyperspectral LiDAR system

Phys.org  May 21, 2023 According to a team of researchers in China the current radiometric correction algorithms used is Lidar has some problems. They proposed an algorithm to overcome the problems. According to the researchers it provides correction equations for intensity and reflectance data recorded by hyperspectral LiDAR. In their tests, according to them, the algorithm achieved good performances by comparing the intensity and reflectance changes before and after removing the leaf incidence angle effect… read more. TECHNICAL ARTICLE 1  ,  2

Scientists achieve single-photon imaging over 200 kilometers

Phys.org  April 5, 2021 The operating range of practical single photon lidar systems is limited to about tens of kilometers over the Earth’s atmosphere, mainly due to the weak echo signal mixed with high background noise. By using high-efficiency optical devices for collection and detection, and new noise-suppression technique that is efficient for long-range applications researchers in China have developed a compact coaxial single-photon lidar system capable of realizing 3D imaging at up to 201.5 km. They developed photon-efficient computational algorithms which enabled accurate imaging with as few as 0.44 signal photons per pixel. The research is a significant step […]

Slow light to speed up LiDAR sensors development

Phys.org  January 14, 2020 Currently existing optical beam steering devices uses mechanics that make them large, unstable, heavy, with limited overall speed and a high cost. Optical phased arrays for steering beams requires many optical antennas. Researchers in Japan used a special waveguide “photonic crystal,” aimed through a silicon-etched medium. Light is slowed down and emitted to the free space when forced to interact with the photonic crystal. They engaged a prism lens to then direct the beam in the desired direction. The resulting method and device are small-sized, free of moving mechanics, setting the stage for a solid-state LiDAR. […]

New lidar instruments peer skyward for clues on weather and climate

Phys.org  May 21, 2019 There is a critical need for vertical measurement profiles of humidity, aerosols, and temperature in the lower troposphere to provide needed coverage for improved weather and climate forecasting across the U.S. There has been a gap in the instrumentation to meet this vision for research and monitoring without relying on aircraft-based devices. A team of researchers in the US (Montana State University, NCAR) has developed diode-based micro-pulse DIAL (MPD) technology as an economical route to a profiler that could make accurate measurements and fulfill desired specifications for continuous, unattended operation and eye safety. The technology will […]