Ultrafast lasers on ultra-tiny chips

Nanowerk  November 10, 2023 Mode-locked lasers (MLLs) generate ultrashort pulses with peak powers substantially exceeding their average powers. However, integrated MLLs that drive ultrafast nanophotonic circuits have remained elusive because of their typically low peak powers, lack of controllability, and challenges when integrating with nanophotonic platforms. Researchers at CalTech demonstrated an electrically pumped actively MLL in nanophotonic lithium niobate based on its hybrid integration with a III-V semiconductor optical amplifier. It generated 4.8-ps optical pulses around 1065 nm at a repetition rate of ∼10 GHz, with energies exceeding 2.6 pJ and peak powers beyond 0.5 W. The repetition rate and […]

Widely tunable and high resolution mid-infrared laser based on optical parametric oscillator

Phys.org  October 18, 2023 A widely tunable and high resolution mid-infrared radiation source operating in the 3–5 µm region has been applied to numerous frontier applications. However, due to the narrow absorption peak linewidth of atmospheric molecules, it is necessary to strictly align the output wavelength with the target wavelength, which requires high wavelength resolution. Researchers in China tuned the temperature and angle of BaGa4Se7 (BGSe) crystals simultaneously placing the crystals in a temperature-controlled furnace, and placed the furnace on an electric rotary platform. This scheme achieved both wide-range wavelength tuning and high-resolution wavelength tuning with stable output wavelength. It […]

Growing triple-decker hybrid crystals for lasers

Phys.org  August 31, 2023 Although two-dimensional organic semiconductor-incorporated perovskites are a promising family of hybrid materials for optoelectronic applications, tuning their structures and specific properties has remained challenging. By choosing the right solvent a team of researchers in the US (Purdue University, Duke University, Lawrence Berkeley National Laboratory) has developed a general method to tune the dimensionality of phase-pure organic semiconductor-incorporated perovskite single crystals during their synthesis. They showed that the length of the conjugated semiconducting organic cations and the dimensionality of the inorganic layers could be manipulated at the same time. The energy band offsets and exciton dynamics at […]

Brighter comb lasers on a chip mean new applications

Phys.org  August 29, 2023 While conventional optical frequency combs are generated using mode-locked lasers that tend to be constrained to high-end scientific laboratories, there has been recent work to develop optical frequency combs using compact, chip-scale microresonators based on dissipative Kerr solitons (DKSs) which consume very little energy, they also do not produce enough output power to be useful. A team of researchers in the US (NIST, University of Maryland) harnessed the newly proposed Kerr-induced synchronization of Kerr solitons to an external stable laser reference to produce optical frequency combs with substantial increase of power on the other side of […]

Generation of color-tunable high-performance LG laser beams via Janus OPO

Phys.org  April 24, 2023 Laguerre-Gaussian (LG) modes of light wave can carry the external torque of photons as they move through space. However, LG mode laser sources do not yet exist. An international team of researchers (China, USA – University of Arkansas) has experimentally demonstrated highly efficient, highly pure, broadly tunable, and topological-charge-controllable LG modes from a Janus optical parametric oscillator (OPO). They designed the Janus OPO featuring a two-faced cavity mode to guarantee an efficient evolution from a Gaussian-shaped fundamental pump mode to a desired LG parametric mode. The output LG mode had a tunable wavelength between 1.5 and […]

Producing extreme ultraviolet laser pulses efficiently through wakesurfing behind electron beams

Nanowerk  February 27, 2023 A team of researchers in the US (University of Michigan, Lawrence Berkeley National Laboratory) has shown, through simulations, that laser pulse surfing in the wake of an electron beam pulse could get upshifted from visible to extreme ultraviolet light. They found phase-matching conditions for the pulse using a tailored density profile. An analytic solution for a 1D nonlinear plasma wake with an electron beam driver indicated that, even though the plasma density decreases, the frequency shift reaches no asymptotic limit, provided the wake can be sustained. In fully self-consistent 1D particle-in-cell (PIC) simulations, more than 40 […]

A liquid laser that is robust in air and tunable by wind

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 […]

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 […]