60 Results Found

We report on the theoretical/numerical investigation of simultaneous second- and third-harmonic generation from a single wavelength input in quasi-phase-matched crystals. The presented technique consists of a quadratic crystal with two first-order qu...

This article deals with a general description of Angular Quasi-Phase-Matching (AQPM) in uniaxial and biaxial crystals for second-order nonlinear optical interactions. Such an exhaustive and generalized angular-dependent approach of AQPM reveals new d...

We report an experimental observation of radiation-induced optical absorption in undoped congruent lithium niobate (LiNbO₃) crystals between the 190 nm and 3200 nm wavelength range. It was found that high-dose (up to 288 Gy) gamma rays did not signif...

We investigate the generation of optical third-harmonic frequency in quadratic crystals with a nonlinear domain lattice optimized with the aid of a random number generator. In the developed Monte Carlo algorithm and numerical experiments, we consider...

Novel methods of coherent short-wavelength sources generation require thorough analysis for their further amendments and practical implementations. In this work, we report on the quasi-phase matching (QPM) of high-order harmonics generation during th...

Random quasi-phase matching (RQPM) in polycrystalline materials has been considered as an important technique for nonlinear optical frequency conversion, especially in wideband laser generation involving femtosecond lasers. In this paper, optical rec...

The results of a study on the effect of pressure in a medium consisting of a set of gas jets separated by vacuum gaps, interacting with two-color laser fields formed by the fundamental and the second harmonics of a laser, are presented herein. It has...

The application of nanoparticles (NPs) and quasi-phase matching (QPM) each play an important role in the enhancement of high-order harmonics (HHG) of ultrashort laser pulses. We analyze various regimes of nanoparticle plasma formation for the creatio...

We present a theoretical investigation on simultaneous generation of two pairs of Stokes and terahertz (THz) waves from coupled optical parametric oscillations (OPOs) with a quasi-phase-matching (QPM) scheme. The two pairs of Stokes and THz waves are...

Advances in Electronics and Optics are often preceded by discoveries in Crystal Growth theory and practice. This article represents in retrospect some of the most significant contributions of heteroepitaxy in these and some other areas—the strong imp...

We demonstrate a compact blue and orange-two color continuous wave laser source emitting at 487 nm and from 597.4 to 600.3 nm, respectively. The temperature tunable coherent orange radiation is achieved by frequency mixing 974 nm laser diode (LD) and...

We report an all-solid-state continuous wave (CW) tunable orange laser based on cascaded single-pass sum-frequency generation with fundamental wavelengths at 1545.7 and 975.2 nm using two quasi-phase-matched (QPM) MgO-doped periodically poled lithium...

Due to the dispersive and multimode natures, only nonlinear Lamb waves with exact phase-velocity matching were generally used in previous studies to evaluate the evenly distributed microstructural evolution in the incipient stage of material degradat...

We report a multi-watt broadband continuous-wave multi-harmonic optical comb based on a frequency division-by-three singly-resonant optical parametric oscillator. This cw optical comb is frequency-stabilized with the help of a beat signal derived fro...

At the time when many nonlinear optical (NLO) materials for frequency conversion of laser sources in the mid and long-wave infrared have achieved their fundamental or technological limits, we propose heteroepitaxy as a solution to develop novel NLO m...

It is well known that bright vortex solitons are unstable in the ${\chi }^{\left(2\right)}$ nonlinear media due to the strong azimuthal modulation instability. To solve this problem, a quadratic (${\chi }^{\left(2\right)}$) $\mathrm{LiNb}{\mathrm{O}}_3$ ferroelectric crystal with a special kind of helical-period...

To rapidly improve strontium optical clocks, a high-power, high-efficiency, and high-beam-quality 461 nm laser is required. In blue lasers based on periodically poled KTiOPO₄ crystals, the optical absorption in the crystals can induce thermal effects...

We propose a novel optical parametric amplification scheme that combines quasi-phase-matching with a composite pulse approach that involves crystal segments of specific lengths. The presented scheme highly increases the robustness of the frequency co...

I present a study of laser-induced plasmas (LIPs) produced on the surfaces of molecular targets to create optimal conditions for high-order harmonics generation during the propagation of femtosecond pulses through the LIP. The resonance enhancement o...

We report development of optical parametric oscillator (OPO)-based mid-infrared laser system that utilizes a periodically poled nonlinear crystal pumped by a near-infrared (NIR) laser. We obtained a mid-infrared average output of 8 W at an injection...

Due to adjustable modal birefringence, suspended AlGaAs optical waveguides with submicron transverse sections can support phase-matched frequency mixing in the whole material transparency range, even close to the material bandgap, by tuning the width...

Periodically poled lithium niobate on insulator (PPLNOI) offers an admirably promising platform for the advancement of nonlinear photonic integrated circuits (PICs). In this context, domain inversion engineering emerges as a key process to achieve ef...

Ferroelectric domain engineering has wide applications in optical and electronic industries. Compared with traditional electric field poling, femtosecond laser poling has many advantages, such as higher fabrication resolution, 3D engineering applicab...

Nonlinear photonic crystals with 3D orthorhombic lattice structures were fabricated using the femtosecond laser-poling technique in ferroelectric Sr_0.28Ba_0.72Nb₂O₆ (SBN) crystals. The crystals were used to demonstrate the possibility of generating ca...

We have demonstrated sum-frequency generation of a compact continuous-wave orange laser in a step-chirped magnesium oxide doped periodically poled lithium niobate in single-pass mode. A 974 nm laser diode was mixed with a C-band amplified spontaneous...

Terahertz (THz) sources, ranging from 0.1 THz to 10 THz, between microwaves and infrared waves, have important applications in spectral detection, medical imaging, communication, etc. Difference frequency generation (DFG) is an effective method for g...

This article describes a gas monitoring system for detecting nitrous oxide (N₂O) gas using a compact mid-infrared laser source based on difference-frequency generation in a quasi-phase-matched LiNbO₃ waveguide. We obtained a stable output power of 0....

Microring resonators made of materials with a zinc-blend or diamond lattice allow exploiting their 4-bar symmetry to achieve quasi-phase matching condition for second-order optical nonlinearities. However, fabrication tolerances impose severe limits...

Entangled photons are essential for photonic quantum technologies. Their generation typically relies on spontaneous parametric down-conversion, but conventional nonlinear crystals are bulky and hard to integrate on chips. Rhombohedral-stacked MoS₂ co...

We demonstrate a method for the realization of highly nonlinear optical 4-(4-dimethylaminostyryl)- 1-methylpyridinium tosylate (DAST) two-dimensional structures by a double-step technique. The desired polymeric structures were first fabricated by usi...

Direct femtosecond laser writing or inscription is a useful technique, and it has been employed to engineer various materials in many applications including nonlinear photonic crystals, which are of periodically patterned second-order nonlinearity to...

We report on the application of femtosecond laser micromachining to the fabrication of complex glass microdevices, for high-order harmonic generation in gas. The three-dimensional capabilities and extreme flexibility of femtosecond laser micromachini...

A bidirectional quasi-endfire patch antenna with a low elevation angle has promising applications for wireless communication systems that are vehicle-based, airborne, and shipborne. In this paper, the shortened patch resonators and open patch resonat...

Potassium titanyl phosphate (KTP) is a nonlinear optical material with applications in high-power frequency conversion or quasi-phase matching in submicron period domain grids. A prerequisite for these applications is a precise control and understand...

This paper aims to consider approximation-estimation tests for decision-making by machine-learning methods, and integral-estimation tests are defined, which is a generalization for the continuous case. Approximation-estimation tests are measurable sa...

The article presents the results of long-term field tests and their mathematical analysis regarding the impacts of innovative phase change materials on the energy efficiency of composite windows with various glazing parameters. Research was conducted...

The global challenge of water resource management presents a policy dilemma: while water resource tax aims to foster green development, it may hinder the economic potential of micro entities. This paper evaluates the efficacy of a trial of water reso...

This study elaborates on the quasi-sliding mode control design for discrete time dynamical systems subject to matched external disturbances and modeling uncertainties. In order to provide finite time convergence to the sliding surface and at the same...

Generally, the development of ship plate steels is mainly concerned with the improvement of strength and toughness, such as F32 and F36. Due to the strength–ductility trade-off, it is difficult to combine excellent ductility with strength impro...

In this paper we investigate the temperature dependent behavior of a liquid crystal (LC) loaded tunable dielectric image guide (DIG) phase shifter at millimeter-wave frequencies from 80 $\mathrm{G}$$\mathrm{Hz}$ to 110 $\mathrm{G}$$\mathrm{Hz}$ for future high data rate communications. The adh...

All actually used SAW sensors have in common that they analyze the transmission characteristics of propagating SAWs. Here, a portable device using the SAW-based impedance sensor type based on one interdigital transducer (IDT) simultaneously as SAW ge...

Recent studies within the physical education domain have shown the superiority of dynamic visualizations over their static counterparts in learning different motor skills. However, the gender difference in learning from these two visual presentations...

In this paper, the electronic, mechanical and thermodynamic properties of AlNi₂Ti are studied by first-principles calculations in order to reveal the influence of AlNi₂Ti as an interfacial phase on ZTA (zirconia toughened alumina)/Fe. The results sho...

In this study, the structural, elastic, and thermodynamic properties of DO₁₉ and L1₂ structured Co₃X (X = W, Mo or both W and Mo) and μ structured Co₇X₆ were investigated using the density functional theory implemented in the pseudo-potential plane w...

This research uses EBSD data of two thermo-mechanically processed medium carbon (C45EC) steel samples to simulate micromechanical deformation and damage behavior. Two samples with 83% and 97% spheroidization degrees are subjected to virtual monotonic...

Recently, there has been growing interest in optimizing exercise protocols in sports training and rehabilitation, with particular attention to eccentric quasi-isometric (EQI) contractions, which involve maintaining joint position until isometric fail...

The authors of this article describe a study designed to support first-grade students’ social studies knowledge and literacy development through a teacher–researcher co-constructed and teacher implemented integrated unit within the contex...

Using van der Pauw method, the conductivity of disk samples of ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3\pm \delta }$ (LSM) and ${\mathrm{La}}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{Co}}_{0.2}{\mathrm{Fe}}_{0.8}{\mathrm{O}}_{3-\delta }$ (LSCF) in a ${\mathrm{Ce}}_{0.9}{\mathrm{Gd}}_{0.1}{\mathrm{O}}_{2-\delta }$ (GDC) matrix was accurately quasi-continuously measured over 800 °C to −73 °C, and the transition points in...

Orbit angular momentum (OAM) has been considered a new dimension for improving channel capacity in recent years. In this paper, a millimeter-wave broadband multi-mode waveguide traveling-wave antenna with OAM is proposed by innovatively utilizing the...

Exciting Fano resonance can improve the quality factor (Q-factor) and enhance the light energy utilization rate of optical devices. However, due to the large inherent loss of metals and the limitation of phase matching, traditional optical devices ba...