Selectivity control on the reaction of alkene with hydrosilane is a challenging task in development non-precious-metal-based hydrosilylation catalysts. While traditional way selectivity relies use different ligand type and/or metals, we report herein that cobalt(I) complexes bearing N-heterocyclic carbene ligands (NHCs) exhibit distinct catalyzing Ph2SiH2. [(IAd)(PPh3)CoCl] (IAd = 1,3-diadamantylimidazol-2-ylidene) an efficient catalyst for anti-Markovnikov monosubstituted alkenes....

Abstract Robust quantum cascade laser (QCL) enduring high temperature continuous-wave (CW) operation is of critical importance for some applications. We report on the realization lattice-matched InGaAs/InAlAs/InP QCL materials grown by metal-organic chemical vapor deposition (MOCVD). High interface quality structures designed light emission at 8.5 μ m are achieved optimizing and precise controlling growth conditions. A CW output power 1.04 W 288 K was obtained from a 4 mm-long 10 m-wide...

Abstract Topological lasers (TLs) have attracted widespread attention due to their mode robustness against perturbations or defects. Among them, electrically pumped TLs gained extensive research interest advantages of compact size and easy integration. Nevertheless, limited studies on been reported in the terahertz (THz) telecom wavelength ranges with relatively low output powers, causing a wide gap between practical applications. Here, we introduce surface metallic Dirac-vortex cavity...

Surface defect passivation and exciton regulation remain a critical challenge in perovskite light-emitting diodes (PeLEDs). Organic molecules are widely used to solve these issues. However, the high sensitivity of films molecular groups concentration limited their commercialization applications. Here, we develop facile low-cost strategy that is compatible with traditional fabrication processes PeLEDs. By depositing thin LiF layer using vacuum thermal evaporation technique, defects film...

In this article, we report a high-performance λ ~ 4.6 μm quantum cascade laser grown by metal-organic chemical vapor deposition. Continuous wave power of 3 W was obtained from an 8 mm-long and 7.5 wide coated at 285 K. The maximum pulsed CW wall-plug efficiency reached 15.4% 10.4%, respectively. device performance shows the great potential deposition growth for material devices.

In this letter, we proposed a kind of high-bandwidth directly modulated quantum cascade laser (QCL) at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 8.5~\mu \text{m}$ </tex-math></inline-formula> by optoelectronic fusion integration technology. Multi-physics collaborative buried heterojunction (BH) QCL with tri-terminal coplanar electrode is monolithically integrated grounded waveguide (GCPW)...

Abstract High-power terahertz (THz) quantum cascade laser, as an emerging THz solid-state radiation source, is attracting attention for numerous applications including medicine, sensing, and communication. However, due to the sub-wavelength confinement of waveguide structure, direct beam brightness upscaling with device area remains elusive several mode competition external optical lens normally used enhance brightness. Here, we propose a metallic photonic crystal resonator phase-engineered...

Abstract: Schizolepis daohugouensis sp. nov. is described from the Jurassic sediments of Daohugou flora, Ningcheng County, Inner Mongolia Autonomous Region, China. The female cone slender, cylindrical in shape, seed scale complexes are loosely and helically arranged on axis at intervals 3–5 mm. scales bilobed divided almost base; have no evident petiole but an articulation region attachment to axis. Each lobe oval widest lower middle part; lobes obtusely pointed with entire margins. Bract...

A comprehensive two-dimensional (2D) reverse phase (RP) liquid chromatography (LC) method is developed for alkaloid analysis. This offline 2D using different pH values. With a value of 10.5, most alkaloids appear in the form neutral molecules possessing high retention factors based on their polarity, while polarity order changed when decreased to 3.0. The performance modulated LC demonstrated with 8 standards which resulted orthogonal separation. then applied total separation Corydalis...

Abstract On‐chip metasurfaces integrated atop optical waveguides have demonstrated the capability of efficiently radiating guided‐waves into arbitrarily prescribed spatial modes by properly tailoring phase distribution in metasurface interface. To date, most on‐chip holographic metasurfaces, typically relying on path multiplexing or wavelength to multiply produced images, encounter certain limitations further enhancing image storage capacity due limited degrees freedom available for devices....

Semiconductor lasers, characterized by their high efficiency, small size, low weight, rich wavelength options, and direct electrical drive, have found widespread application in many fields, including military defense, medical aesthetics, industrial processing, aerospace. The mode characteristics of lasers directly affect output performance, power, beam quality, spectral linewidth. Therefore, semiconductor with power quality are at the forefront international research laser science. novel...

Abstract We demonstrated a scheme of phase-locked terahertz quantum cascade lasers (THz QCLs) array, with single-mode pulse power 108 mW at 13 K. The device utilizes Talbot cavity to achieve phase locking among five ridge first-order buried distributed feedback (DFB) grating, resulting in nearly times amplification the power. Due optimum length depends on wavelength, combination DFB grating leads better than multimode Fabry−Perot (F−P) cavities. facet reflects light back array direction and...

We present a study on the facet damage profile of quantum cascade lasers (QCLs). Conspicuous half-loop strips front are observed when QCLs catastrophically failed. Due to large difference thermal conductivities between active region and substrate, dominant heat is compulsively driven substrate. Abundant accumulation dissipation substrate build temperature gradient lattice mismatch. Thermal-induced stress due sequential mismatch leads occurrence multistep damages facet. Good agreement...

A coupled ridge waveguide quantum cascade laser (QCL) array consisting of fifteen elements with parallel integration was presented. In-phase fundamental mode operation in each element is secured by both the index-guided nature and delicate loss management properly designed geometries ridges interspaces. Single-lobe lateral far-field a nearly diffraction limited beam pattern obtained. By incorporating one-dimensional buried distributed feedback grating, in-phase-operating QCL design provides...

Increasing the power of a quantum cascade laser by widening ridges will lead to degradation beam quality because operation high-order transverse modes. We report on phase-locked array scheme terahertz (THz QCL) utilizing Talbot effect. By adjusting absorbing boundary width each ridge in array, stable fundamental supermode is realized. A five-element shows 4 times amplification than that single device. Due large efficiency, mode selection, and simple fabricating process, very promising...

We present optical frequency combs with a spectral emission of 48 cm −1 and an output power 420 mW based on single-core quantum cascade laser at λ ∼ 8.7 μm. A flat top spectrum sustains up to 130 comb modes delivering 3.2 per mode, making it valuable tool for dual spectroscopy. The homogeneous gain medium, relying slightly diagonal bound-to-continuum structure, promises provide broad stable operating. Remarkably, the dispersion this device is measured within 300 fs 2 /mm ensure operation...

Catalyst-free, vertical array of InAs nanowires (NWs) are grown on Si (111) substrate using MOCVD technique. The as-grown NWs show a zinc-blende crystal structure along < 111 > direction. It is found that both the density and length decrease with increasing growth temperatures, while diameter increases temperature, suggesting catalyst-free governed by nucleation kinetics. longitudinal optical transverse (TO) mode present phonon frequency slightly lower than those bulk materials, which...

We demonstrate surface emitting distributed feedback (DFB) quantum cascade lasers for very high temperature continuous-wave (cw) operation at λ ∼ 4.6 μm. A second-order DFB grating beneath the waveguide provides efficient vertical outcoupling. cw is reported up to a of 75 °C. Total output power 105 mW obtained with record low threshold current density 0.85 kA/cm2 10 Single-lobed far-field radiation pattern divergence angle about 0.17° × 18.7° achieved. Robust single-mode emission side-mode...

We show a phase-locked array of quantum cascade lasers with an intracavity spatial filter based on the Talbot effect. All laser arrays in-phase operation from threshold current to full power near-diffraction-limited divergence angle. The maximum is just about 5 times that single-ridge for eleven-laser device and 3 seven-laser device. structure was analyzed by using multi-slit Fraunhofer diffraction theory, showing very good agreement experimental results. Considering great modal selection...

We report an ultralow power consumption of a quantum cascade laser (QCL) emitting at λ ∼ 4.6 µm operating in continuous-wave mode room temperature. The is achieved by using high gain active region and shortening the device size. For with 0.5-mm-long cavity 3.2-µm-wide ridge, threshold as low 0.26 W optical output 12.6 mW 10 °C mode, which represents world's most advanced level. Furthermore, varies linearly temperature, where linear change rate 2.3 mW/K from to 40 low. As result, devices also...

We demonstrate a long-wavelength infrared quantum cascade detector (QCD) that operates at wavelength of 10 μm, in which the active diagonal transition for electrons occurs from fundamental energy level into miniband adjacent coupled wells. When compared with bound-to-bound transition-based QCD, use as final state increases absorption strength and enhances electron extraction efficiency device, leading to QCD responsivities 75 180 30 mA/W 300 K 10.55 μm operation.

We demonstrate a high power InP-based quantum cascade laser (QCL) (λ ∼ 9 µm) with characteristic temperature grown by metalorganic chemical vapor deposition (MOCVD) in this article. A 4-mm-long cavity length, 10.5-µm-wide ridge QCL high-reflection (HR) coating demonstrates maximum pulsed peak of 1.55 W and continuous-wave (CW) output 1.02W at 293 K. The threshold current density the device is as low 1.52 kA/cm2. active region adopted dual-upper-state (DAU) multiple-lower-state (MS) design it...