Optics and Photonics News April 19, 2019 A team of researchers in the US (University of Rochester, Los Alamos National Laboratory) used feedback loops to optomechanically manipulate the oscillations of a silica nanosphere levitated in an optical trap. In so doing, they were able to create laser-like amplification and coherence of phonons—quanta of vibrational or acoustic energy, analogous to photons in the optical domain. The team believes that the setup opens a general technique for creating frequency-tunable sound lasers in a system-size range that hasn’t previously been explored. The result, according to the researchers, could provide a useful tool both […]
Category Archives: Laser
New shapes of laser beam ‘sneak’ through opaque media
Phys.org March 4, 2019 A team of researchers in the US (Yale University, Missouri University of Science & Technology) used a spatial light modulator (SLM) and a CCD camera to analyze an opaque material that is made of a layer of white paint, biological tissue, fog, paper, and milk. The SLM tailors the laser beam incident on the front surface of the material, and the CCD camera records the intensity profiles behind it. The resulting beam was more concentrated, with more light per volume inside and behind the opaque material. The method works for any opaque medium that does not […]
Lasers can send a whispered audio message directly to one person’s ear
MIT Technology Review January 28, 2019 To send the messages, researchers from MIT Lincoln Laboratory relied upon the photoacoustic effect in which water vapor in the air absorbs light and forms sound waves. The researchers used a laser beam to transmit a sound at 60 decibels (roughly the volume of background music or conversation in a restaurant) to a target person who was standing 2.5 meters away. A second technique modulated the power of the laser beam to encode a message, which produced a quieter but clearer result. The team used it to beam music, recorded speech, and various tones, […]
Terahertz laser for sensing and imaging outperforms its predecessors
MIT News December 10, 2018 For experiments, a team of researchers in the US (MIT, Sandia National Laboratory) fabricated an array of 10 pi-coupled wire lasers which has high constant power, tight beam pattern, and broad electric frequency tuning. The laser operated with continuous frequency tuning in a span of about 10 gigahertz, and a power output of roughly 50 to 90 milliwatts, depending on how many pi-coupled laser pairs are on the array. The beam has a low beam divergence of 10 degrees, which is a measure of how much the beam strays from its focus over distances. The […]
New laser breakthrough: ‘random, transistor’ laser that can be manipulated at nanoscale
Technology.org October 26, 2018 An international team of researchers (Finland, Italy, UK, USA – Case Western University) has demonstrated that can are able to control the direction of a laser’s output beam by applying external voltage. They combined solitons and collinear pumping in weakly scattering dye-doped nematic liquid crystals, whereby random lasing and self-confinement concur to beaming the emission. The advantages are: all-optical switching driven by a low-power input, laser directionality and smooth output profile with high-conversion efficiency, externally controlled angular steering. Such effects make soliton-assisted random lasers an outstanding route towards application-oriented random lasers. This could lead to a […]
Physicists fight laser chaos with quantum chaos to improve laser performance
Phys.org August 18, 2018 The instabilities in the laser are caused by optical filaments, light structures that move randomly and change with time, causing chaos. An international team of researchers (USA – Yale University, UK, Singapore) designed a D-shaped cavity for the laser to induce quantum chaos in the light bouncing around. By creating quantum (wave) chaos in the cavity the laser itself remained steady. The quantum chaos acts on a smaller scale than the wavelength of the light, creating the optical ‘hills’ that help to dispel the optical ‘tornadoes’. They gained insight into the processes and cavity shapes likely […]
Sandia light mixer generates 11 colors simultaneously
Eurekalert June 28, 2018 An international team of researchers (USA – Sandia National Laboratories, Germany) has developed an optical mixer using an array of nanocylinders made from gallium arsenide laid out in a square pattern about 840 nanometers apart from one another. They selected two near infrared lasers with wavelengths tuned to the metamaterial’s resonant frequencies. The light from the two lasers — call them frequencies A and B — mix to produce 11 colors from different mixing products including A+A, A+B, B+B, A+A+B, and A+B+B, and so on. This was accomplished without the need to change angles or match […]