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This work investigates a tunable laser absorption spectroscopy technique for the H 2 O concentration by a Tm:YAP solid-state laser. The output wavelength of Tm:YAP laser is tuned by a birefringence filter and an F-P etalon in the laser cavity. The tuning range is from 1910 nm to 1914 nm, the tuning frequency is 1 Hz. With the tunable Tm:YAP laser, we realize a concentration resolution of 10 ppb. Different concentrations of H 2 O vapor are use to test the precision of the system. A maximum relative error of 0.8% is realized. At the same time, we calculate the maximum absolute error to be 0.8 ppm. Up to the authors’ knowledge, it is the first time to report a tunable laser absorption spectroscopy for the gas concentration measurement by a Tm-doped laser. [ABSTRACT FROM AUTHOR]

This work investigates the feasibility of TDLAS technique in the NO concentration measurement for the marine diesel engine. A system in laboratory is devised for the NO steady state measurement. An ICL laser whose center wavelength is 5263 nm is chosen for the detection. With the direct detection method, a resolution about 2 ppm is realized, and the relative error is less than 5%. In contrast to the direct detection method, the harmonic detection method realizes a higher resolution, and the error is better less 3%. Considering with the temperature fluctuation of the diesel emission, the absorption line strength is calculated from 300 K to 500 K. At the same time, the intensity of the 2f signal is measured, which is proportional to the change of the line strength. So a modification can be imported easily to avoid the error produced by the temperature fluctuation. The TDLAS proposed in this work can realize a high precision, high resolution, and transient measurement for the marine diesel emission. [ABSTRACT FROM AUTHOR]

Developing novel controllable two-dimensional semiconductor materials is crucial to thin film spintronic devices, which may lead to a revolution of information devices. Recently, the easily cleavable CrTe3 has attracted much attention for studying the magnetic properties of two-dimensional materials. In this paper, we have demonstrated theoretically that an elastic tensile strain can turn the antiferromagnetic coupled single-layer CrTe3 (SL-CrTe3) into a ferromagnetic (FM) system, favoring its potential application in thin film spintronic devices. The FM SL-CrTe3 undergoes a further transition from a semiconductor to a metal under a biaxial tensile strain of 9%. The kinetic stability of SL-CrTe3 under 10% tensile strain is verified by a molecular dynamics simulation at room temperature. We suppose that the strain-dependent magnetic behaviors of SL-CrTe3 resulted from the competition between superexchange and direct interactions. The tunable magnetic and electronic properties of SL-CrTe3 imply immense potential in spintronic device applications. [ABSTRACT FROM AUTHOR]

• Magnetism of monolayer CrI 3 can be remarkably tunable by charge doping based on density functional studies. • Li adsorption significantly enhances magnetic anisotropy energy (MAE) of monolayer CrI 3 as predicted by electron doping. • F adsorption may distort CrI 3 , although it can also enhance MAE as hole doping when fixed on the surface. • Li adsorption can also tune the easy axis of CrI 3 from out-plane to in-plane. Magnetic anisotropy energy (MAE) plays a key role for 2D magnetic materials, which have attracted significant attention for their promising applications in spintronic devices. Based on first-principles calculations, we have investigated the influence of surface adsorption on the ferromagnetism and MAE of monolayer CrI 3. We find that Li adsorption can dramatically enhance its ferromagnetism, and tune its easy magnetization axis to the in-plane direction from original out-of-plane at certain coverage of Li. The monotonic enhancement of in-plane magnetism in CrI 3 as the coverage of Li increases are attributed to electrostatic doping induced by charge transfer between Li atoms and I atoms, as supported by the charge doping simulation. The tunable robust magnetic anisotropy may open new promising applications of CrI 3 –based materials in spintronic devices. [ABSTRACT FROM AUTHOR]

A double Q-switch (DQS) Ho:Sc 2 SiO 5 laser modulated by a acousto-optic modulators (AOM) combined with a Cr 2+ :ZnSe saturable absorber (SA) was reported for the first time. The actively Q-switch (AQS) and passively Q-switch (PQS) were also studied. For the DQS mode, a maximum average output power of 2.49 W under the incident pump power of 12.5 W was obtained, corresponding to a slope efficiency of 24%. The characteristics of the DQS Ho:SSO laser versus different repetition frequencies (RF) of the AOM were researched. The maximum single-pulse energy of the DQS Ho:SSO laser was calculated to 1.98 mJ. The maximum peak power of the DQS Ho:SSO laser was 49.5 kW. The output beam quality factor M 2 of DQS Ho:SSO laser was measured to be 1.15 with the highest peak power by knife-edge method at different positions. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenides (TMDs) exhibit many novel properties due to dimension, lattice distortion, electron-electron interaction etc. Here, we determine that 1T-VTe 2 with space group P 3 ‾ m 1 is an antiferromagnetic metal by first-principles calculations, and three metastable structures are predicted, i.e., the P 21 / m and C 2 / m antiferromagnetic semiconductor phases and P 3 m 1 ferrimagnetic half-metal phase. Besides, the C 2 / m phase can be transfered to the P 3 m 1 phase by electron doping, while hole doping can induce a transition from C 2 / m phase to P 3 ‾ m 1 phase. These transitions could be ascribed to a strong coupling of charge, lattice, and spin degrees of freedom in VTe 2. The diverse electronic and magnetic properties of VTe2 provide a good platform for researchers to understand the interactions between spin, charge and lattice. • 1-VTe 2 is clarified to be antiferromagnetic metal ground state. • Three VTe 2 phases with different magnetic states and electronic structures are predicted. • Carrier doping can induce transitions between different phases. • Strong spin-lattice-charge interaction is found in VTe 2. [ABSTRACT FROM AUTHOR]

A compact intra-cavity pumped low threshold continuous-wave Ho:Sc 2 SiO 5 laser is reported. The characteristics of output wavelength tuning are investigated by use a intra-cavity briefringent (BF) filter. A wavelength tunable range of 140 nm from 2020 to 2160 nm is achieved. For the free-running mode, the laser slope efficiency is 24.8%, when the output central wavelength is 2110 nm. The laser threshold is about 820 mW of incident pump power. With the BF filter, a maximum output power of 870 mW is obtained at the incident pump power of 5 W, corresponding to a slope efficiency of 20.3%. The characteristics of output wavelength verse the crystal temperature are also investigated. [ABSTRACT FROM AUTHOR]

Represented here is an electron-optic Q switch Ho:ScSi 2 O 5 laser. A RTP crystal was employed as the Q-switch element. It is the first time to demonstrate an electron-optic Q switch Ho:ScSi 2 O 5 laser, whose maximum single-pulse energy reaches around 102 mJ, corresponding to a maximum peak power of 2.91 MW. The laser performance is investigated as a function of the different repetition frequencies and incident pump power. We focus on the low frequencies (1, 2, 5, 8, 10, and 20 Hz) in this contribution, aiming to obtain a higher single-pulse energy. The beam quality M 2 factor of the electron-optic Q switch Ho:ScSi 2 O 5 laser is measured by knife-edge method, which is calculated to be 1.24. [ABSTRACT FROM AUTHOR]

A widely tunable Holmium-doped ScSiO(SSO) 2 μm laser is reported in this manuscript, which has a wavelength tunable range of 110 nm (from 2050 to 2160 nm). A maximum output power of 3.02 W at 2111 nm is obtained when the laser operates on the continuous-wave free-running mode. A birefringent filter is used to realize the output wavelength tuning, which is put into the laser resonant cavity. The maximum output power of the tunable Ho:SSO laser is 2.07 W. It is the first time to report a widely tunable Ho:SSO laser. The wavelength tunable range is wider than the ones of other Ho-doped lasers and the output power is higher too, which could extend application fields of the Ho-doped lasers. [ABSTRACT FROM AUTHOR]

The antiferromagnetic-semiconductor extreme tensile strain (8%) states of La 0.7 Ca 0.3 MnO 3 membranes was achieved by Hong et al. (2020) [23]. To understand such tunable magnetic and electronic properties in these La 2 3 M 1 3 MnO 3 (M=Ca, Sr) systems, we have investigated the magnetic and electronic behaviors of La 2 3 M 1 3 MnO 3 (M=Ca, Sr) under strain and charge doping using first-principles calculations. A ferromagnetic-semiconductor phase is predicted for La 2 3 Sr 1 3 MnO 3 beyond 4% biaxial tensile strain. Meanwhile, its energy gap and magnetic anisotropic energy increase as the strain increases. We also discover that the change of magnetic exchange energy in La 2 3 Ca 1 3 MnO 3 under charge doping is in analogy to the scenario directly changing the Ca concentrations. Based on the magnetic competition analysis, it is expected that the carrier concentration and strains dominate the magnetic ground state while the La/Ca distributions have little impact. The highly tunable magnetic-electronic properties offer opportunities for the future magnetic-electronic materials design and applications. • DFT SCAN calculations give excellent structure and magnetic moments of the studied systems. • A ferromagnetic semiconductor is predicted for La 2/3 Sr 1/3 MnO 3 under biaxial tensile strain. • Carrier concentration combined with strains dominate the magnetic coupling. • Magnetic anisotropic energy is enhanced by 30 μeV by strains for La 2/3 Sr 1/3 MnO 3. [ABSTRACT FROM AUTHOR]