Phys.org June 11, 2024 Metal phthalocyanines are topical objects of ongoing research and particularly interesting due to their magnetic properties. However, while the current focus lies almost exclusively on spin-Zeeman-related effects, the high symmetry of the molecule and its circular shape suggests the exploitation of light-induced excitation of 2-fold degenerate vibrational states in order to generate, switch, and manipulate magnetic fields at the nanoscale. The underlying mechanism is a molecular pseudorotation that can be triggered by infrared pulses and gives rise to a quantized, small, but controllable magnetic dipole moment. Researchers in Austria investigated the optical stimulation of vibrationally induced […]
Category Archives: Laser
Novel crystals enhance mid-infrared laser performance
Phys.org May 30, 2024 Researchers in China demonstrated a 978 nm laser diode (LD) side-pumped YSGG/Er:YSGG/YSGG composite crystal with a size of Ф 3 mm × 65 mm and continuous-wave (CW) mode. By optimizing resonator length and output mirror transmittance, a maximum output power of 28.02 W was generated, corresponding to slope efficiency of 17.55% and optical-optical efficiency of 12.29%, respectively. The thermal focal lengths were obtained by resonator stability condition. The laser wavelength was centered near 2.8 µm. Moreover, the beam quality factors 2/2 were fitted to be 8.14 and 7.35, respectively. The results indicated that a high-performance 2.8 µm CW laser could […]
Old crystal, new story for enhancing deep ultraviolet laser performance
Phys.org April 1, 2024 Researchers in China obtained 60-mW solid-state deep ultraviolet (DUV) laser at 193 nm with narrow linewidth with two stages of sum frequency generation in lithium triborate (LBO) crystals. The pump lasers were derived from a homemade Yb-hybrid laser. The Yb-hybrid laser was power scaling by a 2mm×2mm×30mm Yb:YAG bulk crystal. The 220-mW DUV laser at 221 nm, and the 193-nm laser delivered an average power of 60 mW with a pulse duration of 4.6 ns. The conversion efficiency reached 27% for 221 to 193 nm and 3% for 258 to 193 nm. According to the researchers […]
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 […]