A double-clad single-mode tellurite optical fiber (DC-SMTOF) with a loss of 0.5 dB/m @1545.1 nm was fabricated based on the TeO2–ZnO–Li2O–Bi2O3 (TZLB) material. During the fiber drawing process, a low level of residual birefringence was produced, which gave a chance for the investigation of the polarization modulation instability (PMI). With a nanosecond laser operated at 1545.1 nm as the pump source

A quantum cascade laser-based infrared spectrometer equipped with a multipass cell has been used to perform sensitive infrared spectroscopy of isoprene at part per billion (ppbv) concentration levels. The instrument was used to measure the absorption of the strong Q-branch of the ν26 vibrational mode of isoprene near 992 cm−1 to determine isoprene concentrations in gas-phase samples. The response of

Energy and spectral–temporal characteristics of lasers on heavily doped single crystals Fe:ZnSe are studied. With the cavity formed by faces of the crystal at a bivalent iron concentration of 2.8 × 1019 cm−3, the slope and total laser efficiencies with respect to the absorbed energy were 53% and ≈ 42%, respectively. Laser spectra with the cavity free of air and elements capable of forming Fabry–Perot

Tomographic measurements of ammonia concentration in diesel engine exhaust dosed with diesel exhaust fluid are demonstrated through spatial scanning of a 10.4 μm quantum cascade laser beam. Optical access through the exhaust pipe was facilitated by a polyimide film. The laser beam was translated in 0.5 cm increments and rotated in 6 degree angular increments, resulting in 2130 unique laser beam positions

Titanium dioxide nanoparticles have been synthesized by the chemical co-precipitation technique and then they have been coated with zinc oxide shell layers using a refluxing method to form TiO2/ZnO core/shell nanoheterojunctions. The physicochemical properties of as-synthesized core/shell nanoheterojunctions have been examined using X-ray diffraction (XRD), Fourier transfer infra-red spectroscopy (FT-IR)

A defective molybdenum oxide (MoO3−x) prepared by a hydrothermal and defect engineering approach was spin-coated on the quartz glass and implemented as saturable absorber (SA). The experiment evidenced that MoO3−x based SA can function as an efficient nanosecond pulse generator, servicing Nd3+, Er3+, Tm3+ doped lasers emission at 1.06 1.64 and 1.94 µm. And the shortest pulse duration of 396 ns, 275 ns

We have investigated the difference between adiabatic and isothermal compression of liquids by an impacting weight, as observed in the resulting change to the index of refraction. The liquids examined were sebacate, glycerol, and water. For practical reasons, sebacate is best suited for the use of a drop-weight apparatus as a metrologically traceable calibration facility for dynamic pressure. We find

We study a method for mass-selective removal of ions from a Paul trap by parametric excitation. This can be achieved by applying an oscillating electric quadrupole field at twice the secular frequency \(\omega _{\text {sec}}\) using pairs of opposing electrodes. While excitation near the resonance with the secular frequency \(\omega _{\text {sec}}\) only leads to a linear increase of the amplitude

We report a tunable single-longitudinal-mode laser based on a wedged Nd:YVO4 gain medium and a YVO4 wave-plate. By taking advantage of the natural birefringence of YVO4 and adopting different cutting methods, a wedged Nd:YVO4 crystal acts as an ideal polarizer by the alignment sensitivity of the optical resonator, and a YVO4 crystal is used as a wave-plate by adjusting the temperature. A theoretical

In this paper, we show that graphene-coated nanowire integrated with a semi-elliptical dielectric substrate could enable excellent subwavelength transmission performance in the mid-infrared range. The fundamental graphene plasmon mode behaviors on the thickness of silica layer, ratio of long- to short-axis of the ellipse, nanowire radius, and chemical potential of graphene are revealed in detail. By

Semiconductors are considered as promising materials for the fabrication of photo-thermo sensors with high sensitivity. Therefore, here we propose to synthesize of amorphous 2D single-layered structures with high thermo-photosensitivity by using photons generated by a KrF* laser radiation (λ = 248 nm, τFWHM ≤ 25 ns) in the reaction of copper (Cu) atoms with methane (CH4) molecules by reactive pulsed

We report on the design and modeling of vertical-cavity surface-emitting laser (VCSEL) integrated in the lateral direction with a cascade of multiple passive cavities. The scheme is proposed to increase the bandwidth of the VCSEL in the mm-waveband to generate ultra-high-frequency oscillations with low-frequency chirp. The model treats the transverse feedback induced by the cascaded transverse coupled

This paper presents new structures for OR, NOT, and XOR logic gates based on a two-dimensional photonic crystal. The proposed structures are quite linear and have the same basic structure for all three gates. Isolation between input ports is one of the features that is given special attention in this study. The proposed designs reduce the leakage signal from an input port to another input port to less

Transverse mode-locking in an end-pumped solid state laser by amplitude modulation with an acousto-optic modulator was investigated. Using the stochastic parallel gradient descent algorithm the modal power coefficients and the modal phases of the transverse mode-locked (TML) laser beam were reconstructed from the measured spatial and spatio-temporal intensity distributions, respectively. The distribution

Simultaneous dual-plane stereoscopic particle-imaging velocimetry (DS-PIV) and hydroxyl planar laser-induced fluorescence (OH-PLIF) was performed at 10 kHz repetition rate in a highly turbulent swirling jet flame. The burst-mode laser system provides sufficient 532-nm dual-pulse energy enabling high-speed large-area dual-plane stereo-PIV measurement. The scattered light from the two planes was separated

Processing method plays an important role in accelerating imaging process in ghost imaging. In this study, we propose a processing method with the Hadamard matrix and a deep neural network called ghost imaging hadamard neural network (GIHNN). We focus on how to break through the bottleneck of image reconstruction time, and GIHNN can identify an object before the imaging process. Our research reveals

Recent advances in wavefront shaping, i.e., wavefront modulated by a spatial light modulator, have opened hopeful venues to focus light through scattering media in particular and unparalleled ways, by means of codifying the values of pixels of the modulator. The transmission matrix approach is one of the most exciting recent advances to obtain optimal phase distributions, due to the consent of enabling

In the paper, based on the linear Schrödinger equation, we analytically investigate the effect of initial chirp on the dynamics of the optical beam in a medium with the parabolic potential. For the linear chirp, the results show that the linear chirp of beam can induce a periodically oscillating behavior, where the oscillating amplitude is proportional to the linear chirp parameter, and the beam’s

Multi-resolution imaging is one of the key means to obtain the target scene information. The Hadamard matrix, which is orthogonal, is an important modulation matrix for single-pixel imaging. In particular, it can provide a good means for multi-resolution imaging. However, as far as we know, studies of high-efficiency multi-resolution single-pixel imaging are rare in the literature. In view of the practical

Dynamic light scattering (DLS) is a widely used, non-invasive and in-situ method for particle size measurement. However, the precision of the measurement results is still under discussion. Theoretically, the apparent hydrodynamic diameter measured by DLS varies with scattering angle due to Mie scattering as well as long-distance interaction between particles. In this paper, a multiple-angle dynamic

We report on the characterization of the angular-dependent emission of single-photon emitters based on single nitrogen-vacancy (NV-) centers in nanodiamond at room temperature. A theoretical model for the calculation of the angular emission patterns of such an NV-center at a dielectric interface will be presented. For the first time, the orientation of the NV-centers in nanodiamond was determined from

The seawater salinity and temperature of an ocean are key parameters required for environmental evaluation, with Raman and Brillouin scattering techniques offering a potentially accurate approach. A method for Brillouin scattering spectrum measurement based on a double-edge technique is proposed, and a retrieval model for simultaneously acquiring Brillouin shifts and linewidths is built. The accuracy

We present directly oscillator-driven self-compression inside an all-bulk Herriott-type multi-pass cell in the near-infrared spectral range. By utilizing precise dispersion management of the multi-pass cell mirrors, we achieve pulse compression from 300 fs down to 31 fs at 11 µJ pulse energy and 119 W average power with a total efficiency exceeding 85%. This corresponds to an increase in peak power

Recently, we reported on the development of a series of Dy-doped organic molecular crystals (with analogous material properties to energetic organic molecular crystals) for use as two-color thermometry phosphors in thermometric imaging of heterogeneous materials under shock compression. In this study, we demonstrate thermometric imaging of one of these phosphors—Dy:Y(acac)\(_3\)(DPEPO)—under pulsed

The dynamics of a model of passively mode-locked laser with saturable absorber, the optical amplifier of which possesses a saturable nonlinearity, is considered with interest in both continuous wave and pulse regimes of operation. The study rests on the laser self-starting picture which assumes that the laser should operate instantly in the pulse regime, when continuous waves become unstable in the

A surface plasmon resonance fiber sensor on the basis of hollow silica capillary (HSC) is theoretically proposed and experimentally demonstrated. Numerical analysis indicates that the structure of multimode–capillary–multimode fiber (MMF–HSC–MMF) possesses high spectral resolution and sensitivity due to the existence of capillary stomata. A 55-nm-thick gold-coated HSC is experimentally implemented

The non-uniform gain of the active media is a significant issue in terms of optimizing the beam profile and ensuring image quality of the laser monitor. In this paper, a study of the radial distribution of radiation in copper bromide brightness amplifiers in real schemes of laser monitors is presented. The radial distribution of radiation in a two-pass parallel beam amplified by a brightness amplifier

Variation of curvature of laser beam changes characteristics of spatially chirped pulsed Gaussian (SCPG) laser beam primarily due to varying spectral divergence. Parametric dependence of different pulse parameters, e.g. angular chirp, pulse front tilt, pulse width, beam radius, radius of curvature etc., is presented for a SCPG laser beam propagating through single and pair of reflective or refractive

Gas sensing by THz wave absorption spectroscopy is demonstrated for several volatile organic compounds (VOCs) using a broadband electronics-based THz wave spectrometer. Spectral absorption is characterized in the frequency range from 220 to 330 GHz for seven VOCs and water vapor in a gas cell at room temperature and pressures of 0.5–10 Torr. Amplitude-modulation is applied to the interrogating radiation

Cd is an extremely toxic element and has a great impact on human health. But the detection of Cd in the soil is still a challenge. This study aimed to improve the analytical ability of laser-induced breakdown spectroscopy (LIBS) to measure Cadmium, the trace elements in the soil. Twelve soil samples containing gradient Cd elements were prepared. The sample concentration was quantitatively analyzed

In this paper, we report a method for rapid water quality evaluation based on laser-excited dissolved organic matter (DOM) fluorescence and water Raman peak. A formula, which results in the score from 0 to 100, was proposed to evaluate water quality. We first employed this method to evaluate the self-prepared water samples with humic acid or fulvic acid under different concentrations from 0.01 mg/L

We demonstrate an interesting modulation of fast electron temperature and yield as a function of the thickness of nanocrystalline coating on a dielectric target, in femtosecond, intense laser interaction with a solid target. We measure the fast electron energy spectrum for fused silica targets coated with ultrathin, nanocrystalline Cu films with thickness ranging from 30 to 100 nm and compare them

A simple and compact single-stage Yb:YAG single-crystal fiber amplifier was setup to amplify 784 fs long seed pulses to an output energy of 6 \(\upmu\)J and an average output power of 290 W. The experimental results are verified by numerical models to estimate the limitations of the SCF technology with regards to beam quality and average output power.

Hyperchaotic maps are generally used in the encryption to generate the secret keys. The number of hyperchaotic maps has been implemented so far. These maps involve a large number of state and control parameters. The major concern is the estimation of these parameters. Because the estimation requires extensive computational search. In this paper, a 7D hyperchaotic map is used to produce the secret keys

In this paper, a rough sample tested interferometrically by intermediate and high coherent red light is demodulated by the wavelet transform (WT) and Fourier transform (FT). The demodulated phase map resulting from the WT is unwrapped by the graph cuts method. A generic equation is given to simulate any parabolic carrier for reference phase map extraction. The unwrapped reference phase map from the

In this paper, a circular core shaped photonic crystal fiber (PCF) is proposed and the optical propagation characteristics are investigated and simulated by applying the finite element method (FEM) with the help of COMSOL Multiphysics software. The cladding of this PCF is composed of fused silica including a large center air-hole. The simulation process is performed within 1000–2000 nm wavelength.

The alkali metal halide salts (KBr, NaBr, KI, NaI and CsI) were used to generate X-rays by femtosecond laser irradiation. Due to a wide band-gap, these materials are transparent and allow generation of X-rays inside the target rather than on its surface. The femtosecond amplified laser system “Pharos” with the wavelength \(\lambda \) = 1028 nm, 4 kHz repetition rate and typical pulse energy 250 µJ

Real-time video-rate passive terahertz imaging systems are highly demanded for practical applications, especially in security checking. Here, we demonstrate a passive video-rate terahertz human body imaging system, which was mainly consisted of a scanning module, a quasi-optical lens, a calibration module and a one-dimensional terahertz detector array. The terahertz waves radiated from human bodies

This paper presents a laser-based absorption technique for measuring temperature and CO concentration in high-pressure shock tubes. Two fundamental vibrations of CO (v" = 0, P8, 4.73 µm and v" = 1, R21, 4.56 µm) were selected for high-temperature sensitivity with a reduced influence from pressure broadening compared to previous work. Single-pass absorption (80 mm path length) was measured with two

A cheap and efficient production of boron isotopes is important for providing further progress in nuclear engineering, semiconductor industry, and nuclear medicine. Motivated by this problem, we consider the \({\text {CO}}_{2}\) laser system designed to separate boron isotopes by the method of laser-assisted retardation of condensation. Values of the basic parameters for this system, such as an acceptable

The nonlinear imaging in laser beam propagation is investigated theoretically under the circumstance that the linear media in the optical path model have arbitrary negative or positive refractive index. Based on the linear diffraction theory and thin-medium approximation, the propagation is solved analytically. Numerical simulation results obtained by split-step Fourier method are also presented. It

This paper presents effect of reflection-induced optical feedback on the post-detection signal power in an intensity modulation-direct detection (IM-DD) fiber optic transreceiver. The detected signal power reduction depends on the reflectivity of the external reflector as well as on the reflectivity of the laser cavity output facet. In the present dual reflector system, any increase in FPLD end facet

A mid-infrared laser absorption sensing method has been developed to quantify gas properties (temperature, pressure, and species density) at MHz measurement rates, with application to annular rotating detonation rocket flows. Bias-tee circuitry is integrated with distributed feedback quantum cascade and interband cascade lasers in the \(4{-}5~\mu \hbox {m}\) range enabling diplexed radio frequency

We report the design and characteristics of a simple and compact mode-locked Er-doped fiber laser and its application to broadband cavity-enhanced spectroscopy. The graphene mode-locked polarization maintaining oscillator consumes less than 5 W of power. It is thermally stabilized, enclosed in a 3D printed box, and equipped with three actuators that control the repetition rate: fast and slow fiber

Ag@ZnO core–shell nanostructures, ZnO nanoparticles (NPs), and Ag NPs were synthesized by laser ablation in water using 8 ns, 1064 nm, and 50 mJ/pulse. The structural, morphological, componential, and optical properties of as-synthesized NPs were examined by X-ray diffraction, transmission electron microscopy, electron diffraction spectrum, and ultraviolet–visible absorption, respectively. The third-order

There is a method that presents for securing much information at the same time, which need not be restricted to a single image data. Based on ghost imaging, this paper proposes a new encryption algorithm: multi-image holographic encryption based on phase recovery algorithm and ghost imaging (PRA-GI). In the encryption process, first, multiple images are combined into one phase hologram image by phase

We report a fully stabilized self-referenced all-solid-state-laser frequency comb based on a home-built Kerr-lens mode-locked Yb:CaYAlO4 oscillator, which delivers ultrafast pulses with a pulse duration of 54 fs and an average power of 1.5 W. Free running carrier-envelope phase offset frequency (fceo) is observed with a signal to noise ratio of 40 dB at 100 kHz resolution bandwidth, which is phase-locked

A tunable terahertz gas laser is demonstrated with a germanium ealton served as the spectrum splitter. The germanium ealton is 1.2-mm thick and anti-reflection coated at 10.17 μm, giving good dichroic performance for infrared and far-infrared radiation. By tuning the incident angle of the germanium ealton, the transmittance of 95% at 9– 11 μm wavelengths and the reflectance of more than 70% at 180 – 500 μm

We report two-wavelength pump-probe measurements of the metastable state lifetime in a high-concentration erbium-doped fiber (EDF). The lifetimes under population inversion conditions are measured using a 980 nm pump laser and a 1.5 µm probe laser. The lifetime variation from the lifetime under low excitation conditions to that of a highly inverted population are calculated using a model derived from

We operate a fiber-based cavity with an inserted diamond membrane containing ensembles of silicon vacancy centers (SiV\({}^{-}\)) at cryogenic temperatures \(\ge 4~\)K. The setup, sample fabrication and spectroscopic characterization are described, together with a demonstration of the cavity influence by the Purcell effect. This paves the way towards solid-state qubits coupled to optical interfaces

We investigate the frequency-resolved intensity noise spectrum of an Yb-doped fiber amplifier down to the fundamental limit of quantum noise. We focus on the kHz and low MHz frequency regime with special interest in the region between 1 and 10 kHz. Intensity noise levels up to \(\ge\)60 dB above the shot noise limit are found, revealing great optimization potential. Additionally, two seed lasers with

Successful operations of quantum-logic-based \(^{27}\hbox {Al}^+\) ion optical clocks have been reported by several groups. But there are still several lingering issues. The first is the proper choice of logic ions, and the second is the proper quantum state identification methods. In this paper, the advantage of using \(^{25}\hbox {Mg}^+\) as the logic ion to ensure smaller time-dilation shift is

A polarization-maintaining (PM) fiber-coupled acousto-optic modulator (AOM) was used, in the present work, to tailor the stable 3.523 picosecond (ps) mode-locked pulses generated by an all PM fiber oscillator. The pulse clusters with 7.315 MHz, 731.5 kHz, and 73.15 kHz of repetition rate were obtained. The number of pulses in each pulse cluster could be adjusted from 1 to 6. Through the harmonic mode-locked

Compact nonlinear frequency conversion of a Y-branch distributed Bragg reflector (DBR) diode laser for alternating dual-wavelength laser emission at 532 nm is presented for the very first time. The developed light source, realized on a 5 × 25 mm2 micro-optical bench, is based on single-pass second harmonic generation of a 1064 nm Y-branch DBR diode laser in a periodically poled lithium niobate waveguide

Unfortunately, the first author name was incorrectly published in the original publication

It is crucial to understand the behavior of the optical properties of soot in the visible and near-IR spectral range to calculate the magnitude of their emission and absorption. Such information also helps in the development of diagnostic methods for soot. We measured the absolute value of the refractive index functions of soot nanoparticles E(m,1064) at a wavelength of 1064 nm, as well as the ratio

Terahertz (THz) air coherent detection is a broadband coherent detection technique, which has been used widely in the THz science and technology. In this paper, a frequency-dependent response function of THz air coherent detection is defined based on the nonlinear polarization of gas molecules induced by the ultrashort laser pulses and the THz pulses. Calculations show that the response function of

It is believed for a long time that optical quality of liquid gain-medium (dye solution) of high pulse-repetition-frequency dye laser is degraded by its turbulent flow but so far this belief is not verified by direct experiment. We have devised a novel experiment to study the exclusive effect of turbulent flow on the optical quality of the dye solution pumped by copper vapour laser. The experiment

The primary aim of this work was to study the diseased and healthy rice plant samples at the elemental and molecular level to get the proper understanding of the causes and the chemical changes occurred in the healthy rice grains with the infestation due to false smut disease. We have used microscopic and isolation methods to detect and identify the presence of the species of pathogen involved in the