Phys.org February 9, 2023 Avalanche photodiodes (APDs) have internal gain, which means that when compared to PIN-photodiodes they typically have a higher signal-to-noise ratio. Researchers in the UK designed and demonstrated photodiode that exhibits high multiplication factor with very little added noise. The new semiconductor alloy is based on a GaAsSb absorption region that has excellent detection efficiency at infrared wavelengths (up to 1,700 nanometers). The device incorporated an appropriate doping profile to suppress tunneling current from the absorption region, achieving a large avalanche gain, ∼130 at room temperature. It exhibits extremely low excess noise factors of 1.52 and 2.48 […]
Tag Archives: LIDAR
A new strategy for active metasurface design provides a full 360-degree phase tunable metasurface
Phys.org May 2, 2022 Active metasurfaces have been proposed as one attractive means of achieving high-resolution spatiotemporal control of optical wavefronts, having applications such as LIDAR and dynamic holography. An international team of researchers (South Korea, USA – University of Wisconsin) has developed an electrically tunable metasurface design strategy that operates near the avoided crossing of two resonances, one a spectrally narrow, over-coupled resonance and the other with a high resonance frequency tunability. It displayed an upper limit of 4π range of dynamic phase modulation with no significant variations in optical amplitude, by enhancing the phase tunability through utilizing two […]
New LiDAR Sensor Uses Mirrors to Achieve High Efficiency
IEEE Spectrum August 21, 2020 An international team of researchers (USA – University of Florida, China) designed and fabricated a MEMS mirror specifically designed with direct actuation from the microcontroller. It is powered by a 9-V commercial battery. Instead of a motorized optomechanical scanner, the system relies on MEMS mirrors to control the LiDAR signals. The mirrors require significantly less power to manipulate than the bulkier motorized scanner that have typically been used. A passive infrared sensor ensures that the whole system is only activated when people are present. It may have applications ranging from robotics to small unmanned air […]