Phys.org February 10, 2023 Lasers made solely from liquids are promising toward flexible lasers, but they are intrinsically unstable and have been inapplicable to steady operation under ambient conditions unless they are enclosed in a tailored container or a matrix to prevent the evaporation of the liquid. To simulate the near-perfect water droplets that form on the lotus leaves and roll off, an international team of researchers (Japan, Germany) mixed 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) with a dye that allowed it to become a laser. The droplets were highly robust and worked as efficient long-lasting laser oscillators. The lasing wavelength was sensitively […]
Category Archives: Laser
Building off the ‘anti-laser,’ researchers create a device that directs waves.
Phys.org January 26, 2023 Building off a breakthrough “anti-laser,” an international team of researchers (France, USA – Yale University) has developed a system that can direct light and other electromagnetic waves for signal processing without any unwanted signal reflections. Instead of transducing it into another form of energy, the device redirected to specific channels. It could either all go into chosen output channels or some of it could be absorbed and the rest go into the output channels. In the next step, they want to make a similar device where the absorption is negligible, so that all the energy is […]
New single-mode semiconductor laser delivers power with scalability
Phys.org June 29, 2022 A team of researchers in the US (UC Berkeley, Lawrence Berkeley National Laboratory) created a new type of semiconductor laser, dubbed Berkeley Surface Emitting Lasers (BerkSELs), that can maintain a single mode of emitted light while maintaining the ability to scale up in size and power. The BerkSEL design enabled the single-mode light emission because of the physics of the light passing through the holes in the membrane, a 200-nanometer-thick layer of indium gallium arsenide phosphide. The periodic holes in the membrane became Dirac points. By eliminating the need for external amplification, they could shrink the […]
Generating ultra-violet lasers with near-infrared light through ‘domino upconversion’ of nanoparticles
Phys.org May 19, 2022 Direct ultraviolet lasing is constrained by the fabrication challenge and operation cost. Researchers in China have developed a strategy for the indirect generation of deep-ultraviolet lasing through a tandem upconversion process. They developed a core–shell–shell nanoparticle to achieve deep-ultraviolet emission at 290 nm by excitation in the telecommunication wavelength range at 1550 nm. The ultra large anti-Stokes shift of 1260 nm (~3.5 eV) stems from a tandem combination of distinct upconversion processes that are integrated into separate layers of the core–shell–shell structure. By incorporating the core–shell–shell nanoparticles as gain media into a toroid microcavity, single-mode lasing at 289.2 nm was realized […]
Laser bursts drive fastest-ever logic gates
Phys.org May 11, 2022 Recently it was experimentally demonstrated that strong non-resonant few-cycle laser pulses can be used to induce phase-controllable currents along gold–silica–gold nanojunctions in the absence of a bias voltage. Since the effect depends on a highly non-equilibrium state of matter, its microscopic origin is unclear and the subject of recent controversy. An international team of researchers (Germany, USA – SLAC National Accelerator Laboratory, University of Rochester, Georgia State University, Los Alamos National Laboratory, Canada) has presented atomistically detailed electronic transport simulations that recover the main experimental observations and offered a simple intuitive picture of the effect. The […]
Intense laser light modifies the pairing of electrons
Phys.org April 12, 2022 Researchers in Germany have realized a method to affect and measure the effective exchange interaction between several electrons bound in a molecule with two differently colored laser pulses. Using soft X-ray light, they excited an electron deeply bound to the sulfur atom in a sulfur hexafluoride molecule, thereby extending its radius of motion to the entire molecule for a short time before it leaves the molecule. Due to the spin-orbit interaction of the deeply bound electrons remaining there, the hole formed at the sulfur atom thereby produces a characteristic double structure of two lines measurable in […]
A new record for laser stability across atmospheric distances
Phys.org January 24, 2022 The propagation of laser through turbulent atmosphere is affected by wind and minor equipment vibrations. Researchers in Australia used a host of features to keep the beam stable, including temperature controls, noise reduction and automatic adjustments to the devices holding the equipment. The test involved sending a beam from a building to a site 1.2 kilometers away. The target consisted of a mirror to bounce the laser beam back to a device near the source of the laser. The beam was held in place for approximately five minutes. Once a long-distance means of sending laser signals […]
When graphene speaks, scientists can now listen
Phys.org January 19, 2022 Laser-induced graphene (LIG) can be patterned on a variety of substrates using a laser scriber/cutter. The quality and morphology of LIG is currently analyzed using Raman spectroscopy and electron microscopy. Researchers at Rice University have developed a new method to analyze LIG in real-time during the synthesis using a microphone attached to the laser writing head, followed by a simple acoustic signal processing scheme. They demonstrated that it is possible to use the same energy input to simultaneously drive the conversion process and probe the formation of LIG in situ by applying Fourier and integral analyses, […]
New laser meets demanding requirements for driving cutting-edge attosecond light sources
Phys.org October 1, 2021 Researchers in Germany have combined a fiber-laser system with multi-pass cells to create a laser with a combination of few-cycle pulses at high average power, pulse energy and repetition rate and with stable carrier envelope phase (CEP) operation. The system coherently combines eight amplifier channels. It emits 300-fs pulses that are then compressed down to the few-cycle regime using two multi-pass cells. The first multi-pass cell uses standard dielectric mirrors and the second cell uses metal-based mirrors. With further improvements, they hope to achieve less than 300 mrad of CEP noise. The laser system opens new […]
Trapping light with disorder
Phys.org October 5, 2021 A random laser has many degrees of freedom that are not available in conventional cavity lasers. Based on this discovery, an international team of researchers (Israel, France) showed that laser emission can be simply controlled by shaping the pump profile that provides the gain inside the scattering medium. This is done optically with total flexibility. They found that selective excitation significantly reduces the lasing threshold, while lasing efficiency is greatly improved. Their spatial locations are critical to boost laser power efficiency. By efficiently suppressing the spatial hole burning effect, they could turn on the optimally outcoupled random […]