The distribution of laser Compton scattered (LCS) photons in the energy-angle phase space reflects the parameters of the laser and electron beams at the collision point and provides the spectral density and bandwidth available in the LCS source. Diagnosis of the energy-angle phase space is thus crucial for developing high-flux and narrow-bandwidth LCS sources. Such diagnosis has been utilized for photon

Thermal expansion properties are investigated for Ti 2 O 3 -based sintered polycrystalline materials by controlling crystal lattice parameters and porous structures. Negative thermal expansion (NTE) is observed in a temperature range between room temperature and 593 K, and found to exceed Δ L / L = −0.7% at high temperatures, in spite of continuous increase of the unit cell volume. The temperature

We characterized surface plasmon polariton (SPP) coupling in InGaN/GaN nanocolumn (NC) arrays with Ag- and Au-based plasmonic crystals (PlCs). In both the Ag- and Au-based NC-PlCs, the standing wave SPPs enhanced the light emission from the InGaN/GaN NC arrays. The finite-difference time-domain calculations reproduced the general tendency of the experimental results for the photoluminescence enhancement

Measuring the polarization state of light has become a challenging study owing to its requirement to simultaneously extract the phase and amplitude parameters with high precision. Here, we present a weak measurement (WM) scheme with two pointers to determine a general polarization state. For the output spectrum from the WM regime, one pointer with the light frequency is used to measure the phase parameter

Conductance of thin (18 nm) silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor is investigated from the viewpoint of metal insulator transition (MIT). Conductance characteristics taken in the parameter space defined by the front- and back-gate voltages in a temperature range on the order of 10 K reveal that the critical conductance G C , separating the metallic and insulating

High-temperature CO 2 treatments for 4H-SiC(0001) surfaces and SiO 2 /SiC structures were investigated. A stoichiometric SiO 2 insulating layer was found to be grown on SiC by thermal oxidation in atmospheric CO 2 ambient with an activation energy of 7.5 eV. Post-oxidation annealing (POA) in CO 2 at a temperature of 1200 °C or more was effective in reducing interface fixed charges, oxide traps, and

MEMS mirror arrays perform superior than MEMS mirror to assemble a Lidar, but few published papers about the optical intensity and distributions when laser diffracted by MEMS arrays are available, this letter focuses on the issues. Firstly, the complex amplitudes of laser which is diffracted by 1D (dimension) and 2D arrays are presented, respectively. Then we give the optical intensity and distributions

We investigated the electron transport properties of parallel-coupled double quantum dot (DQD) devices under magnetic fields. When a low magnetic field was applied, electron tunneling through parallel-coupled DQDs was observed. Under a high magnetic field, we observed both electron tunneling through parallel- and series-coupled DQDs under nonlinear transport conditions. In addition, the Pauli spin

Constructing mixed heterostructures are often designed as a photoelectrocatalytically active interface to facilitate the separation of photo-induced charge carriers, thus improving photoelectrochemistry device performance. Herein, two dimensional Ti 3 C 2 /MoS 2 heterostructures were successfully synthesized by liquid phase exfoliation and electrophoretic deposited methods. The photocurrent density

Thermal neutron (∼25 meV) beam is a powerful tool for investigating the structure and properties of materials used in science and technology. A laser-driven neutron source generating 10 10 neutrons within 1 ns duration is utilized to a single shot radiography with a dual beam of thermal neutrons and X-rays. As a proof of principle, we show the non-destructive inspection of hazardous substances (Cadmium)

A large topological Hall effect was observed in Mn 2 PtSn epitaxial thin films. The non-hysteretic topological Hall resistivity can be attributed to the canted spins below the reorientation temperature, while the hysteretic topological resistivity in the vicinity of the zero field captures the trend of antiskyrmion formation. A decrease in thickness enhances the contribution of dipolar interactions

Different from the abruptly autofocusing induced by the linearity, we report a new type of abruptly autofocusing induced by the defocusing nonlinearity. By investigating the dynamics of the outward-focusing ring Pearcey–Gaussian (PeG) beam in defocusing nonlinear media, it is found that the propagation of the beam exhibits an abruptly autofocusing behavior of simultaneous intensity (the degree of the

Gaps in metal structures are accompanied by strong field enhancement (FE) and localized electromagnetic effects. However, completely different characteristics are presented when the microgaps and nanogaps in metallic structures are imaged using THz s-SNOM. We find that the near-field signal profile measured across the gap varies significantly with the ratio of the tip apex radius to the gap width.

An interesting evolution of spin glass behaviors and the corresponding exchange bias effects were observed by quenching Ni 50 Mn 42 In 3 Sb 5 Heusler alloys at different temperatures. When the alloy is quenched at 1173 K, it will freeze from antiferromagnetic to spin glass at low temperature under an external magnetic field, creating a giant exchange bias field up to 9063 Oe through the pinning effect

Photonic crystal resonators with the C 4v symmetry were designed and fabricated on quantum cascade lasers with a strain-compensated multiple quantum well to achieve single-mode and vertical surface emission at 4.32 μ m. Their fabrication accuracy was confirmed by high-resolution reflection spectroscopy. The maximum output power was 10 mW at 77 K. A far-field pattern with a small divergence angle below

A magnetic Bloch line (BL) is a nanoscale topological defect with a nontrivial topological charge. Herein, we propose a novel memory that utilizes current-driven BL motion. We demonstrate that it is possible to write and shift BLs using a spin-transfer-torque scheme. The writing efficiency and shifting velocity of the BL-based racetrack memory are better than or comparable to those of domain wall (DW)-based

The temperature dependence of ferroelectric properties was investigated for (Al 0.8 Sc 0.2 )N films 9–130 nm thick prepared on (111)Pt/TiO x /SiO 2 /Si substrates. The coercive fields ( E c ) of these films decreased with increasing measurement temperature up to 523 K, irrespective of film thickness, thus realizing polarization switching because the applicable maximum electric field is beyond E c

Temperature-dependent current–voltage characteristics was measured to investigate leakage conduction mechanisms in GaN-on-Si quasi-vertical Schottky barrier diode. At low reverse bias, thermionic emission is dominated. At voltage range from −1 to −20 V, variable range hopping (VRH) is main leakage current mechanism at low temperatures (298–373 K), while at high temperatures (498–573 K), electrons gain

We investigated the effect of device parameters on intermediate-frequency (IF) output power in sub-harmonic mixing by an anti-parallel diode pair based on Fermi-level managed barrier (FMB) diodes. The IF output power peaked as the local oscillator (LO) power increased due to the saturation of the FMB diode itself. The peak IF output power was found to increase as barrier height increased while it stayed

We demonstrate a self-starting tunable all-normal-dispersion (ANDi) ytterbium (Yb):fiber laser based on the biased nonlinear amplifying loop mirror (NALM), which generates a stable femtosecond dissipative soliton with an average output power of 154 mW at a pump power of 816 mW. It has a dechirped pulse duration of 178 fs, a repetition rate of 88.6 MHz. Taking advantage of the intracavity-birefringence

A superconducting quantum interference device (SQUID) comprising 0- and π -Josephson junctions (JJs), called π -SQUID, is studied by the resistively shunted junction model. The π -SQUID shows half-integer Shapiro-steps (SS) under microwave irradiation at the voltage V = ##IMG## [http://ej.iop.org/images/1882-0786/14/10/103001/apexac211dieqn1.gif] {$({\hslash }/2e){\rm{\Omega }}(n/2)$} , with angular

We demonstrated the coincidence measurement of quantum light by superconducting nanowire single-photon detectors with a single-flux-quantum (SFQ) circuit as a signal processing circuit. By the quantum state tomography of a polarization-entangled photon pair, we evaluated the detection system based on the SFQ coincidence circuit. The estimated fidelity was almost the same value as that measured by using

The full InGaN structure was grown on two different InGaNOS substrates from Soitec. An electron blocking layer was inserted in the full InGaN light emitting diode (LED). Enhanced internal quantum efficiency of red emitting InGaN/InGaN quantum wells was measured with a value above 10% at 640 nm. 10 μ m diameter circular micro-LEDs are emitted at 625 nm with an external quantum efficiency of 0.14% at

We report on a refractive-index waveguide AlGaN-based ultraviolet-B band (UV-B) laser diode grown on a sapphire substrate, which achieves a laser oscillation at a low threshold current ( I th ), ∼85 mA. The refractive index waveguide structure in a ridge-type structure is fabricated by a unique method combining dry inductively coupled plasma reactive ion etching and wet etching with tetramethylammonium

This letter proposes an all-solid-state, ultra-low sidelobe optical phased array (OPA) by arranging the broadband metasurface units in the mid-infrared band. Simulation results demonstrate that the OPA generates a specific or a continuous beam sweep between 0° and 42.22° as the 354.56° phase modulation of the designed metasurface. A key feature of our design is that the maximum sidelobe energy of the

We developed an in situ measurement system based on a synchrotron radiation nanobeam X-ray diffraction technique combined with a pump–probe method to investigate lattice deformation induced by the inverse piezoelectric effect in AlGaN/GaN high-electron-mobility transistor devices. Static and dynamic measurements using ultrafast X-ray pulses successfully captured changes in the c -plane lattice spacing

We report on the development of high-conductivity carbon nanotube (CNT) tapes with high stability at elevated temperatures (220 °C) by a two-step FeCl 3 -doping process at ambient pressure. Raman spectroscopy, electron microcopy, and thermogravimetric analysis reveal that this robust behavior is ascribed to the retentiveness of the dopants in the CNTs. These results advance the development of CNT tapes

This work investigates an abnormal rising current in high resistance state (HRS) during the reset process that occurs when increasing the sweeping set compliance current (SCC). When the SCC is increased, the HRS current read at a lower voltage (−0.1 V) remains similar, yet exhibits a gradual rise when read at a higher voltage (−0.8 V). In order to clarify this abnormal phenomenon, the current fittings

This letter reports an impact of SiN film stress on electroluminescence (EL) of AlGaN/GaN HEMTs. The EL color of HEMTs turned from high-intensity white to low-intensity red, as the SiN film stress was increased from −24.2 (compressive) to +11.5 MPa (tensile). The weak reddish EL from the HEMT with a film stress of +11.5 MPa turned bright whitish when a drain-to-source voltage ( V ds ) was increased

Realizing a high-contrast anti-scattering light focusing by using a spatial light modulation such as a digital micromirror device (DMD) demands a robust optimizer in the process of wavefront shaping. Genetic algorithm (GA) as a common practice can easily be stuck into the inferior local minima. Here, we combined GA with encoding neighboring pixels of DMD to circumvent the inferior local minima. Simulations

An effective method for studying the relationship of dielectric functions and thickness in perovskite SrRuO3 (SRO) thin film was proposed by spectroscopic ellipsometry measurement. A wedge-shaped SRO film with various thickness was prepared on SrTiO3 substrate by pulse laser deposition, whose dielectric functions and thickness were obtained by using the Drude–Lorentz dispersive model. The acquired

We propose a pair of coupled nanowires (PCNWs) and examine light trapping in PCNWs with various diameters based on the finite-difference time-domain simulation. We demonstrated that light absorption in PCNWs could be significantly tuned via engineering light coupling mainly due to the reshaped and strengthened leaky mode resonances. The photocurrent of PCNWs is remarkably enhanced by 24.1% than a pair

We realize the unidirectional reflectionless light propagation in metal-insulator-metal plasmonic waveguide side-coupled with two resonators based on bulk Dirac semimetal (BDS). This phenomenon is observed at exceptional points where the parity-time symmetry is broken, and near perfect absorption is obtained. Based on the dynamic tunability of BDS, the ultra-compact structure with adjustable unidirectional

We report on a novel high power vertical cavity surface emitting laser (VCSEL) with high order shallow surface grating, which enables a single mode operation even for 6mm long devices. A high single mode power of over 3W is obtained under pulsed operations for a 6mm long oxide aperture. A fan-shape beam with sub-degree narrow divergence is obtained up to high injection currents of 5A. Thanks to the

A method of magnetocardiography (MCG) measurement using an overdamped bistable model based stochastic resonance (SR) technique for advancing biomagnetic sensors is proposed. To determine the system parameters for SR, an evolutionary algorithm combined with the coherent detection (CD) method is applied. We acquire and process an animal MCG at room temperature, detected by a commercially available optically

A vertical electrical conductivity of an ultrawide bandgap AlGaN p–n junction with Al-composition-graded Al x Ga1−x N (0.45≤x) p-type layer was systematically investigated via experiments and numerical simulation. The experimental results revealed that the initial Al composition of the Al-composition-graded AlGaN should be sufficiently high without Mg dopants to generate enough holes by polarization-induced

We achieved a harmonic-rich signal from linear magnetization responses of magnetic nanoparticles under 40 μT/μ 0 excitation field to facilitate magnetic particle imaging (MPI). In contrast, large harmonic responses are typically attributed to the nonlinear field-dependent magnetization characteristics of the particles, thus questioning technical and clinical issues toward a human-sized MPI scanner

Conventionally, tuning magneto-optical Kerr rotation via the excitation of surface plasmons (SPs) usually results in extremely low light energy at the Kerr null point position in the optical spectrum. Realizing independent control of the magneto-optical effect is considered as an effective solution. The decoupling between the Kerr effect and optical response is achieved in our constructed Ag/Co composite

We propose a novel method to generate p-type conduction and low resistivity in wide- and ultrawide-bandgap III-nitride semiconductors via doping of a magnetic element. This method is based on the energetic competition between the covalency of the magnetic element and the ligand nitrogen atoms and the exchange-correlation energy of the magnetic impurity. Using magnetic elements with large exchange-correlation

Iron selenide telluride, FeTeSe, is an attractive layered material for both superconductivity and spintronics applications. FeTeSe enables Ising-type superconductivity, which involves spin-momentum locking. We report superconductivity of mechanically exfoliated thin film FeTe0.6Se0.4 that equips ferromagnetic electrodes with perpendicular magnetic anisotropy to detect possible Ising spin paring. The

We present the design and experimental verification of a membrane-type resonator-based Schroeder diffuser (MRSD). The membrane-type resonator consists of a decorated membrane and a rigid back cavity. By combining multiple resonators with the phase shift profile based on the quadratic residue sequence, the MRSD can produce a high efficiency diffuse sound field. Furthermore, the designed MRSD has a thickness

Complementary metal-oxide-semiconductor inverters featuring steep voltage-transfer characteristics (VTC) were successfully fabricated on 4H-SiC(0001) substrates. Even without nitridation of the MOS interfaces, well-balanced n- and p-channel field-effect transistors were realized by means of ultrahigh-temperature gate oxidation (HTO) at 1600 C under reduced oxygen partial pressure. Improvements in the

We report on the spintronic terahertz (THz) emission from a Ni/Pt bilayer on MgO grown via electron beam deposition. The films were grown with varying Ni thicknesses with a constant Pt thickness. The nominal Ni thickness values of 3, 5, 7, 9, 15, and 23nm exhibited thickness-dependence of the THz emission intensities which was well-fitted with a model by Torosyan et al. Thickness-dependence was also

Tertiary battery, which can be charged by heating and/or cooling, is a promising energy harvesting device that performs energy conversion during the thermal cycle between low and high temperatures. Here, we investigated the performance of the Na x Co[Fe(CN)6]0.87 (NCF87)/Na x Ni[Fe(CN)6]0.94 (NNF94) tertiary battery made of paste-type electrodes between 10 and 50 C. Its performances, i.e. thermally-induced

Ultra-low voltage drop tunnel junctions (TJs) were utilized to enable multi-active region blue light emitting diodes (LEDs) with up to three active regions in a single device. The multi-active region blue LEDs were grown monolithically by metal-organic chemical vapor deposition (MOCVD) without growth interruption. This is the first demonstration of a MOCVD grown triple-junction LED. Optimized TJ design

We propose and demonstrate an all polarization-maintain fiber (PMF) mode-locked laser based on nonlinear polarization evolution without any splicing angle. In this laser, the complex optimization of the fused splicing angle between PMFs can be avoided and high modulation depth is achieved through using a special polarization beam splitter. By simply adjusting pump power, the environmentally stable

We report on efficient terahertz-wave generation in organic and inorganic crystals by nonlinear wavelength conversion approach using a 3.3μm femtosecond pulse laser. Experimental results reveal the relation between pump power and terahertz-wave output power, which is proportional to the square of the pump power at the range of mega- to tera-wattcm−2 class even if the pump wavelength is different. Damage

Recently, with the development of optically induced artificial magnetism, the Kerker effect has attracted renewed interest in various branches of nanophotonics. Here, we extend this effect into the acoustic system and present a rigorous analytical model for discussing the generalized Kerker conditions related to directional forward or backward scattering. A two-dimensional cylindrical acoustic Mie

A p-GaN gate high electron mobility transistor (HEMT) based monolithic bidirectional switch with diode bridge structures is demonstrated. The bidirectional switch features four recessed anode Schottky barrier diodes embedded in a p-GaN HEMT, which effectively reduces the on-state voltage and minimizes the parasitic elements. The proposed device exhibits a high threshold voltage of 1.84V, a low on-state

We investigate characteristic fluctuations in multi-quantum well (MQW)-based waveguides whose absorption spectrum experimentally changes as a ∼5nm blue shift when dielectric passivation layers are employed. We theoretically show that the blue shift corresponds to a ∼0.03% compressive strain in the MQW resulting in a group refractive index change (Δn g ) of ∼−0.01. The estimated Δn g agrees with an

This paper describes the use of flash lamp annealing (FLA) to fabricate high-Sn content GeSn n-MOSFETs. We exploit FLA processing for both impurity activation and for the solid-phase growth (SPG) of the GeSn channel. High-Sn incorporation of up to 12% is achieved by overcoming the solid-solubility limit of Sn in Ge (1%), and high-quality n+-source/drain junctions were obtained by P implantation and

In this letter, we proposed a compact multimode fiber (MMF)-based laser scanning endoscope (LSE) using wavefront shaping with a liquid crystal spatial light modulator. Experimentally, we demonstrated the lensless imaging capability of the LSE using a negative USAF-1951 test target placed near the distal MMF facet, obtaining ∼7000-pixel images with micro-level spatial resolution and high contrast across

The ratio of the photoionization cross sections () of carbon substituting at the nitrogen site [CN (0/−)] in n-type GaN, which is detected as a hole trap H1 (+0.85eV) under sub-bandgap-light irradiation (390nm), is determined with isothermal capacitance transient spectroscopy (ICTS). The current-injection ICTS and the sub-bandgap-light-excited ICTS were compared for the same p+-n junction diode, whereby

We present a low-frequency dual-band (303 and 356Hz) perfect acoustic absorption (PA) metaporous. The metaporous composite is constructed by introducing Helmholtz resonance and Fabry–Prot resonance in porous materials. Our simulations show that the dual-band metaporous absorber has an ultra-thin thickness (λ/18 for 356Hz). Using the coupling of the three dual-band PA absorbers, the low-frequency high-efficiency

Antiperovskite manganese nitride compounds possess the saturation characteristics of the mean free path at an approximate room temperature. Therefore, such compounds show a flat resistance–temperature curve at an approximate room temperature. In this paper, we propose a manganese nitride resistor for high-thermal-stability systems. We fabricated and evaluated the micro/nanoscale manganese nitride compound

To simultaneously evaluate the switching performance and cost (required chip size) of GaN vertical-trench metal-oxide-semiconductor field-effect transistors, we calculated R on AR on Q g considering the Miller effect with various cell pitches, channel mobilities, and blocking voltages. When the blocking voltage was 600V, optimized cell pitches of 8 and 12μm minimized R on AR on Q g with channel mobilities

Superior thermal performance of GaN/graphite composite (GC) bonded substrates having an ultralow thermal resistance (R th) has been demonstrated. Thermal transition in GaN-on-GC features fast relaxation process in GaN and slow case in GC, respectively. The temperature plateau at the GaN/GC interface indicates the R th across this interface is quite small and hence can be ignored. High-quality bonding

We demonstrate that the structure of output frequency spectra emerges asymmetric behavior between the left and the right driving in a coupled whispering-gallery-mode microresonators with a spinning microresonator due to the Sagnac–Fizeau shift. In addition, the high-order sidebands generation with higher orders (about 60) can be obtained with experimentally achievable parameters, and the frequency

In this study, the photovoltaic behavior of centimeter-long lateral organic junctions, reaching 1.8cm, is reported. The organic junctions are formed using organic semiconductor films with high mobilities of holes and electrons. The lateral diffusion lengths of photogenerated electrons and holes are 4.7 and 5.5mm, respectively. The photovoltaic behavior in the centimeter-long lateral junctions is controlled

GaInNAs junctions can be applied to the lattice-matched five-junction (5J) or six-junction (6J) solar cells to achieve ultra-high efficiency. In this work, a GaInNAs solar cell integrating distributed Bragg reflectors (DBR) is grown by metalorganic vapor phase epitaxy. According to external quantum efficiency measurements, the photocurrent can be improved by ∼20% due to DBR. Meanwhile, a short-circuit