Phys.org June 6, 2022 Quantum states of light have been shown to enhance precision in absorption estimation over classical strategies. However, most quantum sensing schemes rely on special entangled or squeezed states of light or matter that are hard to generate and detect. Researchers in the UK have shown it is possible to perform high precision measurements of important physical properties without the need for sophisticated quantum states of light and detection schemes. The key to this breakthrough is the use of ring resonators that guide light in a loop and maximize its interaction with the sample under study. Importantly, […]
Category Archives: Sensors
Optimizing the Sensitivity of Biological Particle Detectors through Atmospheric Particle Analysis According to Climatic Characteristics in South Korea
Sensors 2022, 22(9), 3374 March 31, 2022 Researchers in South Korea optimized an environmentally adaptive detection algorithm that can better reflect changes in the complex South Korean environment than the current models. The algorithm distinguished between normal and biological particles using a laser-induced fluorescence-based biological particle detector capable of real-time measurements and size classification. It operates with minimal false alarms in any environment by training based on experimental data acquired from an area where rainfall, snow, fog and mist, Asian dust, and water waves on the beach occur. The detection performance for each level of sensitivity was examined to enable […]
Acoustic sensors to pinpoint shooters in an urban setting
Phys.org May 23, 2022 Instead of a sound propagation-based approach, researchers in Germany focused on an information theoretical analysis using the Cramér-Rao bound to predict the achievable shooter localization accuracy. They showed that accounting for incomplete and heterogeneous acoustic measurement data sets leads to maximization of the fusion gain and consequently to improved achievable localization accuracy. They validated the match between predicted and actual experimental performance in free-field measurements with supersonic gunshots including varying sensor-to-shooter geometries, weapon types, and various measurement types. By measuring signatures of impulsive gas cannon shots in urban terrain, they analyzed the effect of buildings to […]
Scientists turn a hydrogen molecule into a quantum sensor
Science Daily April 22, 2022 Researchers at UC Irvine positioned two bound atoms of hydrogen in between the silver tip of the scanning tunneling microscope (STM) and a sample composed of a flat copper surface arrayed with small islands of copper nitride. With pulses of the laser lasting trillionths of a second, they were able to excite the hydrogen molecule and detect changes in its quantum states at cryogenic temperatures and in the ultrahigh vacuum environment of the instrument, rendering atomic-scale, time-lapsed images of the sample. The STM was equipped to detect minute electrical current flowing in this space and […]
Nanomaterials: Light dependent atom clusters for sensing applications
Phys.org April 1, 2022 An international team of researchers (Japan, France, Germany, Switzerland) has developed a new environment-sensing device based on the opto-ionic-electronic phenomena of an octahedral molybdenum metal (Mo6) cluster. When the Mo6 cluster is electrochemically deposited on a transparent electrode in an organic solvent containing a trace amount of water, the water permeates the deposited film. During the process, some ligand species that stabilize the frame structure of the Mo6 cluster are substituted with hydroxyl groups, and the negatively charged frame structure of the Mo6 cluster unit is stabilized by hydronium counterions. As a result, the transparent film […]
Nano particle trapped between mirrors works as a quantum sensor
Science Daily April 7, 2022 In an optical resonator light is reflected between mirrors, and it interacts with the levitated nanoparticle. Such interaction can give rise to dynamical instabilities which are often considered undesirable. An international team of researchers (Austria, Switzerland) has shown how they can be used as a resource. They have shown that by properly controlling these instabilities, the resulting unstable dynamics of a mechanical oscillator inside an optical cavity leads to mechanical squeezing. They applied this approach to a silica nanoparticle coupled to a microcavity via coherent scattering. The new protocol is robust in the presence of […]
Blow flies can be used to detect use of chemical weapons, other pollutants
Phys.org March 24, 2022 Blow flies sample the environment as they search for water and food sources and can be trapped from kilometers away using baited traps. Researchers at Purdue University exposed three species of blow flies to the chemical warfare agent (CWA) simulants dimethyl methylphosphonate and diethyl phosphoramidate as well as the pesticide dichlorvos, followed by treatment-dependent temperature and humidity conditions. At intervals within a 14-day postexposure period the fly guts were extracted and analyzed. They found that the amount of CWA simulant in fly guts decreased with time following exposure but were detectable 14 days following exposure, giving […]
Light derails electrons through graphene (w/video)
Nanowerk March 24, 2022 An international team of researchers (Spain, USA – Columbia University, Japan, Singapore) showed that by applying circular polarized infrared light onto the bilayer graphene device, they could selectively excite one specific valley population of electrons in the material, which generated a photovoltage perpendicular to the usual electron flow. By engineering the device and setup in such a way that current only flows with light illumination, they were able to avoid the background noise that hampers measurements and achieved a sensitivity in the detection several orders of magnitude better than any other 2D material. They could control […]
Novel quantum sensing possibilities with nonlinear optics of diamonds
Phys.org March 22, 2022 Taking advantage of the properties, especially the harmonic generation of nitrogen vacancy in diamond researchers Japan have presented an efficient and viable way for creating diamond-based nonlinear optical temperature sensing. Using infrared ultrashort pulse laser stimulation, the team found that the harmonic generation decreased with temperature over the range of 20–300°C. The temperature-dependent change was explained by mismatch due to the speed of different colors of light in the diamond. As the atomic lattice heats up, the difference in the index of refraction between the original light and the higher energy light created by harmonic generation […]
Physicists create compressible optical quantum gas
Phys.org March 24, 2022 The compressibility of a medium, quantifying its response to mechanical perturbations is a fundamental property determined by the equation of state. For gases of material particles studies of the mechanical response are well established in fields from classical thermodynamics to cold atomic quantum gases. Researchers in Germany demonstrated the measurement of the compressibility of a two-dimensional quantum gas of light in a box potential and obtained the equation of state for the optical medium. The experiment was carried out in a nanostructured dye-filled optical microcavity. They observed signatures of Bose-Einstein condensation at high phase-space densities in […]