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 […]
Category Archives: Laser
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 […]
Non-stop signal achieved in high-power Erbium-doped mid-infrared lasers
Phys.org July 1, 2021 Based on their previous research work on laser, researchers in China further improved the laser performance of Er:YAP laser crystal by laser-diode side-pumping method. A Er:YAP crystal rod with concave end-faces was used to compensate the thermal lensing effect. They achieved maximum output power of 26.75 W at 250 Hz, and 13.18 W at 1000 Hz. They demonstrated a LD side-pumped and electro-optical Q-switched Er,Pr:YAP laser with emission at 2.7 μm. A giant pulse laser was obtained with pulse energy of 20.5 mJ, pulse width of 61.4 ns, and peak power of 0.33 MW at the […]
Researchers produce laser pulses with record-breaking intensity
Phys.org May 6, 2021 A team of researchers in South Korea demonstrated laser intensity exceeding 1023W/cm2 with the CoReLS petawatt (PW) laser. After wavefront correction and tight focusing with a two-stage adaptive optical system and an f/1.1 (=300mm) off-axis parabolic mirror, they obtained near diffraction-limited focusing with a spot size of 1.1 µm (FWHM). From the measurement of 80 consecutive laser shots at 0.1 Hz, they achieved a peak intensity of (1.1±0.2)×1023W/cm2, verifying the applicability of the ultrahigh intensity PW laser for ultrahigh intensity laser–matter interactions. From the statistical analysis of the PW laser shots, they identified that the intensity […]
Researchers develop first self-cooling laser made with a silica fiber
Phys.org March 17, 2021 An international team of researchers (USA – Stanford University, University of Illinois, Clemson University, Sweden, Canada) has achieved laser cooling in silica optical fiber with 21-µm diameter core doped with ytterbium and co-doped with aluminum oxide and fluoride ion to increase the critical quenching concentration by a factor of 16. Using a custom slow-light fiber Bragg grating sensor they measured temperature changes up to −50mK. The measured dependencies of the temperature change on the pump power and the pump wavelength were in excellent agreement with predictions from an existing model. To understand how fiber composition, core […]