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Variety applications such as laser displaying, entertainment industry, materials processing, defence and astronomy research require high-power lasers at specific wavelengths of visible spectrum range. Frequency conversion of high-power IR laser radiation in nonlinear-optical crystals is one of the most efficient ways to generate high-power visible radiation [1]. Creating artificial inverse polarized...
Mid-IR is considered a molecular fingerprint region that is particularly suitable for sensitive chemical detection in the atmosphere. In the recent years quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) become semiconductor sources of choice for high resolution spectrometry in the mid-IR. An ideal spectroscopic system should provide simultaneous spectroscopic detection of large molecules...
Ethylene (C2H4) is known to be a plant hormone significantly affecting the growth, ripening, and decay of fruits [1], an important biomarker reflecting people's health condition [2], and a primary pollutant in promoting the formation of tropospheric ozone in urban areas [3]. The detection of C2H4 at parts per billion (ppb) — parts per million (ppm) concentration levels is crucial in numerous applications...
We investigate plasmon excitation on the surfaces of a thin metal-film grating, which are sinusoidally modulated with a common period and different initial phases. Employing Yasuura's method of modal expansion, we numerically find the resonance angle, field distribution, power flow in the vicinity of the grating surfaces, and efficiency of propagating orders. By setting the amplitude of the metal-film...
Graphene plasmons are collective excitations of charges within the 2D sheet of carbon atoms. A strong energy confinement, low group velocities and high tunability, make graphene plasmons exciting candidates for plasmonic applications in the THz to mid-IR range. In contrast to most metallic and semiconductor materials graphene plasmons can strongly couple to the particle/hole plasma due to a unique...
With the rapid development of photovoltaic (PV) technology, ultrathin crystalline silicon (c-Si) solar cells (SCs) with the thickness of only 10 ‼ 20 µm have attracted tremendous attention due to the reduced material loss and a high photoelectric conversion efficiency (PCE). However, the shortened active layer decreases the optical-path of incident light substantially and thus lowers optical absorption...
Terahertz Photonics is an emerging field with a great amount of potential science and applications. Functional optical technologies to control the amplitude, phase and polarization of Terahertz waves are crucial for advancing the THz technology. In this work, we study the coherent perfect absorption (CPA) [1] of a chiral structure and show its potential use as polarization control for THz waves.
A simplified one-pot reflux heating synthesis of CdTe quantum dots (QDs) is introduced. As a result, the absorbance of CdTe QDs has a linear dependence on the Te:Cd molar ratio. Both the absorption intensities and the first absorption peaks increase linearly as the reaction time increases. The concentration of as-prepared CdTe QDs increases slower and the photoluminescence brightness decreases when...
Compared with conventional drying technology, microwave assisted drying technology has some remarkable properties, such as material-selective, instantaneous and volumetric heating, which leads to extremely broad applications in materials drying. The efficiency of microwave drying is found to be dependent on various factors, such as temperature, moisture content, the dimension of material and so on...
In systems with suitable symmetries, topologically protected states can arise that are immune to perturbations. We discuss how the properties of such states can be enriched via the charge-conjugation symmetry, which in condensed-matter physics is associated with Majorana quasiparticles in a superconductor. In particular, this symmetry plays a central role in the selective amplification of topologically...
Following the work of Bender et al. [1], systems with parity and time symmetry (that is, they are invariant under a mirror reflection and complex conjugation) have been extensively studied. The interesting aspect of PT-symmetric theory is to replace the traditional condition that the Hamiltonian of a quantum system must be Hermitian with the weaker condition that it combines parity and time symmetry...
The electromagnetic wave absorption mechanism of conductorbacked electromagnetic wave absorbers with periodically arranged conductor patterns on the surface layer (pattern absorbers) was investigated. The pattern absorbers in this work were composed of a patterned layer acting as a frequency selective surface, such that the pattern served as a resonator together with a back reflector. Electromagnetic...
We theoretically demonstrate a convex-concave organic solar cell based on two-dimensional arrayed silica (SiO2) dielectric nanospheres loaded above the indium tin oxide (ITO) substrate, which can bring efficient light trapping in the active layer. In simulation, the PEDOT: PSS (buffer) and the PSBTBT:PC71BM (active) layers are conformal to that of the SiO2 nanospheres, i.e., in the convex-concave...
Microwave assisted heating technology has become a popular alternative to conventional heating technologies with the characteristics of selectivity, instantaneity, integrity, safety, environmental friendliness and efficient energy-saving. Microwave absorption characteristics of material are critical because it provides an important index of utilization efficiency of microwave energy. However, a debate...
Selective wave-transmitting absorbers (STAs), which have one or more narrow transmission bands among a wide absorption band are often demanded in wireless communication and stealth technology. They can be used in many applications such as reducing antennas' radar cross section, reducing the coupling between different systems and improving anti-jamming capability. However it is difficult to realize...
Recently, a new lidar technique for atmospheric remote sensing based on Scheimpflug principle referred to as Scheimpflug lidar (SLidar) [1–3], was developed. When a laser beam is transmitted into the atmosphere, the implication of the Scheimpflug principle is that the backscattering echo of the entire illuminated probe volume can still be in focus simultaneously without diminishing the aperture, as...
We demonstrated that the three-dimensional metamaterial absorbers, consisting of the resistive patches and metallic backboard, can exhibit ultra-broadband and highly efficient absorption for a certain larger incidence of the transverse magnetic wave. The three-dimensional unit cell is constructed by bending the resistive patches, which is arranged at a certain period on the metal plate. Comparing...
We theoretically investigated the optical absorption properties of graphene monolayer on the top of the truncated dielectric photonic crystals deposited on a prism in the visible range. Perfect absorption are realized since the Bloch modes are excited on the surface of the graphene monolayer. Furthermore, it is found that total absorption can be achieved at special oblique incident angles for both...
In this paper, we propose a polarization-independent and broadband perfect metamaterial absorber operating in mid-infrared region. The proposed absorber is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones, which can control gray- or black-body thermal signatures. The simulation is implemented using CST Microwave Studio. The simulated results show that the proposed...
During the past decades, there has been great interest in studying the magneto-optical (MO) effects because of their potential applications for optical readout of magnetically stored information in erasable video and audio disks [1]. In general, the MO effects are caused by the interaction of light with magnetized materials or nonmagnetic media in the presence of the external magnetic field We study...
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