An optical isolator with a low insertion loss and high isolation is desirable for quantum networks and modern optical communication. Here, we realize an optical isolator with the far-off resonant Raman process in a thermal Λ-type atomic system. The experimental results show a high isolation, ultra-low insertion loss, and widely tunable frequency simultaneously. The maximum isolation is more than 30 dB

Filament-induced breakdown spectroscopy (FIBS) is an analytical method that holds significant promise for remote sensing. In FIBS, it is desirable to maximize the intensity and improve the reproducibility of a selected spectroscopic feature. We demonstrate the use of wavefront control in conjunction with a genetic algorithm in FIBS of metallic copper and show that this approach can increase the efficacy

The performance of ring resonators, as any other optical device, have been analysed and it is the purpose of many recent studies, due to their multipurpose optic response. Ring resonators can work as filters, amplifiers, modulators, repeaters or multiplexers. Recent studies show that optical sensors based on ring resonators is designed to achieve high sensitivities sensors for non-invasive diagnosis

We demonstrate the periodic interconversion evolution of the double-charge vortex (DCV) and out-of-phase (OOP) quadruple solitons in two-dimensional (2D) optically induced Lieb photonic lattices by single-site excitation under appropriate self-focusing nonlinearity conditions. The numerical results show that the DCV evolves into a rotating quasi-vortex soliton, utilizing an OOP quadrupole-like beam

We study creation of entanglement and quantum steering in a parity-time- (PT -) symmetric cavity magnomechanical system. There are photon-magnon coupling and phonon-magnon coupling in this system. By introducing a gain cavity mode, a PT -symmetric Hamiltonian of the system is obtained. We find that bipartite entanglement and magnon→phonon steering in PT -symmetry system (gain-loss system) are significantly

To design a dense multi-pass cell (MPC) with optimized spot pattern, a quasi-variance analysis method is proposed and by which the MPC’s spot deformation is investigated. We put forward a design scheme of a dense double spherical coaxial mirror MPC with optimized spot pattern. By using the ABCD transmission matrix without paraxial approximation, a calculated spot pattern which is very close to the

We theoretically and experimentally demonstrated the existence of dual loss peaks in the transmission spectrum of long-period fiber gratings (LPFGs) fabricated in a parameter-optimized two-mode fiber for the mode coupling between LP01 and LP11 modes by CO2 laser. The two dips moved in opposite directions with decreasing grating period and merged at a critical grating period. The strain and temperature

We observe the rotational Doppler shift of an orbital angular momentum-carrying ring Airy Gaussian vortex (RAiGV) beam based on the rotational Doppler effect (RDE) for the first time. The Airy Gaussian beam has attracted a considerable interest in recent years owing to its autofocusing characteristics which indicates an important potential use in optical trapping. Here we propose a scheme for spinning

Based on the inversion characteristic of the truncated Airy pulse in linear regime with third-order dispersion (TOD), we discuss the related dynamics of the truncated Airy pulse in a nonlinear femtosecond optical system. The influence of the initial total power and the Airy pulse width on the nonlinear effect is studied in detail. The results show that when the initial total power is less than one

Based on Box–Behnken Design of response surface methodology, multiple experiments of laser drilling (four centimeters thickness of sandstone) were performed by continuous fiber laser (Model MFSC) with a maximum laser power 1 kW to obtain the specific energy of rock with three experimental parameters of laser power (400∼800 W), irradiation time (6∼10 s) and spot diameter (0.01∼0.03 m). According to

Sampling frequency offset (SFO) will result in phase rotation, inter-channel interference, and inter-symbol interference, which can seriously degrade the transmission performance of the asynchronous direct-detection optical OFDM (DDO-OFDM). In this paper, we study a simple and overhead-free SFO blind estimation technique in a DDO-OFDM system. The key parameters in this technique are optimized by theoretical

In this letter, we present a compact and low cost smartphone based oblique incidence reflectometer (OIR) for the measurement of tissue optical properties in vitro. The proposed lightweight OIR system obliquely delivers a narrow laser light by the attached inexpensive laser diode onto the surface of the matter under test. The incident laser light produces a spatial distribution of diffuse reflectance

Line-scanning microscopy with virtually structured modulation (vLSM) provides an easy, low-cost, axial laminating ability, and phase-artifact-free strategy to achieve super-resolution imaging. In this paper, we apply the nonlinear reconstruction (NLR) algorithm to the vLSM and obtain rapid super-resolution imaging. The reconstruction algorithm can directly process raw data in the spatial domain without

In recent years, optically controlled phased array radar has been widely used because of its high radiation power, flexible beam steering and anti-electromagnetic interference, but the radar system based on discrete devices is still plagued by the problems of large size, high power consumption and complex control method. In this paper, we propose a two-dimensional integrated optical true time delay

We have modeled a novel reconfigurable optical absorber using the array of the rectangular nanoparticle array based on the Metal–DNA–Metal (MDM) structure and discussed the effect of the DNA composite on electric field distribution by switching to “On” and “Off” modes based on low conductivity (LC) or high conductivity (HC) attributes of the material. In this structure, we have assumed a model of the

The active tuning of surface waves supported by left-handed materials (LHMs) is a major challenge for their practical applications and usability, and graphene has been proposed as an agent for the active tuning of surface waves. In this study, tunable surface waves supported by graphene-layered LHM structures are investigated theoretically. The analytical and numerical results are computed for transverse

The results of theoretical and numerical studies of finite one-dimensional (1D) three-periodic photonic crystals of the structure [(ab)3(cd)3]3, consisting of four different materials (dielectric oxides Al2O3, SiO 2, TiO 2, and ZrO 2) are presented. We study the transmittivity spectra and partial energy fluxes of the TE- and TM-modes in the range of 1–5 μm in the vicinity of the first photonic bandgap

Random scattering media that scatters incident light waves for optical diffraction-limit break imaging has important application prospects and significance in biomedical imaging, lithography micromachining and nanomaterial surface shape analysis. However, the transmission matrix, which represents the relationship between incident and output pixels in monochromatic image detecting through scattering

Fringe Projection Profilometry is one of the important techniques in three-dimensional vision. However, traditional Fringe Projection Profilometry employing a lot of patterns has significant challenges for efficiently recovering the absolute phase. In this paper, a multi-purpose neural network combining with code-based patterns is proposed to recover the absolute phase firstly, which can greatly decrease

Free space optical communications (FSO) have the potential to substantially improve communications technology in terms of channel capacity and offer an alternative to their RF counterpart. Additional characteristics related to security, immunity, flexibility and low cost issues render FSO a reasonable candidate for military applications. FSO technology does not come without challenges. Its major issue

Orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) is a promising modulation candidate for passive optical network (PON) due to its high flexibility, better time–frequency focusing characteristic, great resistance to the inter symbol and inter carrier interferences and higher spectrum efficiency compared to OFDM. However, the intrinsic imaginary interference

Imaging simulation of a dark field imperfection evaluation arrangement for spherical optical surface is proposed on the basis of reverse ray tracing. A typical evaluation arrangement for optical element surface imperfections seen in reflection under dark field condition is introduced. As for thin lens, it is a common case that light spots naturally emerge in the field of view (FOV) and dark field condition

We experimentally demonstrate a photonic microwave frequency measurement based on polarization interference by measuring DC voltage. Time delay is introduced into two electric signals which serves as driving signals of the parallel Mach–Zehnder modulators. After polarization interference, the amplitude of DC output is related to the microwave frequency. Thus, the system can identify the input frequency

We study the influence of few-layer graphene on omnidirectional photonic band gap (OPBG) in one-dimensional photonic crystal (1DPC) at terahertz frequencies. By periodically introducing few-layer graphene into 1DPC, the width of OPBG can be greatly broadened. As the layer number of introduced graphene increases, the broaden effect of the OPBG becomes stronger. The physical reason behind the broaden

Scattering limits the acquisition of object information and reduces the probe depth. Imaging correlography method utilizing scattering light has shown its advantage in visualization deep through dynamic multiple scattering medium. However, there is a lack of boundary condition to use it specifically. Here, we propose a new criterion for imaging correlography based on optical properties of dynamic multiple

An ultracompact mode-order converting power splitter using a multimode interference (MMI) coupler with subwavelength gratings (SWGs) is proposed for mid-infrared (MIR) wavelength. Two symmetric oblique SWG-wires are embedded in the central input-region that is connected with the input waveguide. As a result, the input TE0 mode is evenly coupled from the input waveguide into the MMI coupler due to the

We investigate the dynamics of Pearcey-Gaussian pulses propagating in a multimode fiber. By solving the nonlinear Schrödinger equation with the split-step Fourier-transform method, the propagation of Pearcey-Gaussian pulses in the multimode fiber is revealed. It shows an interesting phenomenon that under the combined action of second-order dispersion and third-order dispersion, multiple breathing solitons

Free-space optical communication links experience atmospheric turbulent light intensity fluctuation fading, which requires accurate channel parameter estimation to ensure stable communication. In this paper, the maximum likelihood (ML) method is proposed to estimate composite Gamma–Gamma fading channel parameters. The ML estimation expression based on the expectation maximization (EM) to compute unknown

In this paper, Q-switched pulses were generated for the first time in a holmium-doped fiber laser (HDFL) incorporating a niobium carbide-polyvinyl alcohol (Nb2C-PVA) film-based saturable absorber (SA). At a pump power of 285.7 mW, Q-switched pulses were observed with a repetition rate of 20.5 kHz and a minimum pulse width of 4.4 μs. The Q-switched spectrum was centered at 2079.5 nm with a 3-dB bandwidth

The performance of modulating retro-reflector (MRR) free space optical (FSO) communication system has been studied before for various atmospheric turbulence conditions. However, the effect of pointing error (PE) on the MRR FSO communication system has not been studied yet. In this work, we investigate the PE impact on the MRR FSO communication system. Specifically, we obtain the probability density

Active manipulation of dual transparency windows for EIT metamaterial in dark–bright–dark coupling mode, which is constructed by three graphene patterns, including graphene strip and two asymmetrical double-split graphene ring resonators, is numerically and theoretically investigated in terahertz regime. Simulation results illustrate that the causation of dual-windows EIT phenomenon is the near field

The generation, manipulation, and detection of beams carrying orbital angular momentum (OAM) has acquired paramount importance in a wide range of applications, from imaging to information and communication technology. To this aim, optical conformal mappings have been designed and implemented to transform light beams in an efficient and controlled way. In this paper, we analyze for the first time the

Performing imaging with scattered light is challenging due to the complex and random modulation imposed upon the light by the scatterer. We overcame these restrictions by combining the transmission matrix methods with the Muller matrix polarization decomposition. We built a polarization imaging device for a strongly scattering medium and demonstrate our experiment. Image enhancement and denoising were

In the ultrasonic-assisted water confined laser micromachining silicon, micro-cracks may generate. The effect of ultrasonic power and thickness of the water layer on the groove section’s micro-cracks is discussed systematically to control the micro-cracks formation and improve the processing quality. The experimental and simulational results indicate the maximum radius of the bubbles and the bubble

The multiple-input multiple-output (MIMO) technique for free-space optical (FSO) system was initially designed for combating fading events in the diversity mode. However, as people demand for higher throughput, extra freedom can be obtained from the multiple apertures in the spatial multiplexing mode, where the system transmits independent parallel data streams over multiple apertures to increase data

This paper proposes a novel image data augmentation method based on the 4F optical diffuser system with two spatial light modulators. The method combines data augmentation methods based on geometric transformations with optical phase diffuser, resulting in a system which is effective and easy-to-use. This method can be used in an all-optical machine learning system or in a hybrid digital-optical system

In this paper, an asymmetric photonic crystal fiber (PCF) polarization filter near the gold-clad hole based on surface plasmon resonance (SPR) is proposed. The outer walls of the two air holes in the y-direction are coated with a gold film, and the two kinds of cladding air holes are introduced near the coated holes to increase the difference in the coupling strength of x and y polarization modes and

We theoretically study nonreciprocal optical bistability in a three-level Λ-type atomic system with the Doppler broadening within a unidirectional ring cavity. The results show that the nonreciprocity optical bistability can be realized by means of the forward or backward probe field propagation. Under the appropriate parameters, the optical isolation ratio and the width of the optical nonreciprocity

In this paper, photonic generation and transmission technique for multi-format microwave waveform is proposed. In the center office, a broadband optical source (BOS) is utilized as optical carrier. And the main component is a dual-polarization dual-drive Mach–Zehnder modulator (DPol-DDMZM) followed by a polarization division multiplexed emulator (PDME). The DPol-DDMZM consists of two sub-DDMZMs to

In this work, we further researched the influence of heavy atom on the electroluminescent (EL) performances of organic light-emitting diodes (OLEDs) containing thermally activated delayed fluorescence (TADF) materials as emitters by utilizing iridium(III)bis(4’,6’-difluorophenylpyridinato)tet-rakis(1-pyrazolyl)borate (Ir(mppy)3) as the host of the assistant light-emitting layer (EML) and 2-[4-(dip

Investigation on the relative phase evolution between two bounded optical solitons is essential for its potential applications in development of larger telecommunication capacity of optical fiber transmission lines, resolution improvement in advancing ultrafast characterization approaches and development of all-optical information storage. Here we characterized relative comb-line phase jitter power

In this paper, we prepared a low cost, environmentally friendly and stable surface enhanced fluorescence (SEF) substrate, namely, Ag@razor clam (Ag@RC), for fluorescence enhancement via magnetron sputtering technique. When the magnetron sputtering time was 10 min (Ag-10), we obtained optimal fluorescence enhancement effect for this substrate. The maximum enhancement factor (EF) for rhodamine 6G (R6G)

A broadband high-efficiency polarization-independent double-layer slanted grating for RGB colors is presented in this paper. The double-layer transmission grating with a graded refractive index is designed by rigorous coupled-wave analysis (RCWA) and simulated annealing (SA) algorithm. The diffraction efficiency of the -1st order can reach more than 84% within the wavelength range from 454 nm to 630 nm

Comparing with electronic beam forming, integrated optical beam forming is very promising for optical controlled phase array system, because much broader band beam steering can be achieved without the beam squint effect. The single channel optical true time delay lines based on the cascade microring resonators and switched optical delay waveguides have been extensively investigated. The optical beam

The edge effects of high-power slab lasers cause severe wavefront distortions with large amplitude and gradients, which is a great challenge for the adaptive optics systems for improving the beam qualities. The standard least-squares wavefront reconstruction method would inherently assign higher priorities to correcting the edge aberrations which contribute little to the laser power in the near diffraction-limit

The aero-optical aberration of conformal dome (AOACD) is difficult to correct and would cause serious image degradation. Wavefront coding (WFC) image technique includes the optics and the digital processing steps to achieve the final high-quality images and it can be used to control the optical aberrations. In this paper, a strategy for correcting the AOACD is presented based on WFC technology. The

The use of noninvasive multi-parametric imaging platforms to guide pathological diagnosis and therapeutic procedures can significantly improve clinical outcomes. A hybrid optical imaging modality integrating laser speckles, image fusion processing, and temperature measurement was utilized to monitor dynamic parametric responses in live tissue. Speckle imaging, based on two laser sources, was employed

A scheme of dual-loop optoelectronic oscillator (OEO) based on a directly modulated distributed feedback (DFB) laser is proposed and experimentally demonstrated. In the proposed scheme, thanks to the DFB laser with enough output optical power utilized as an optical source and a modulator at the same time, high-performance microwave signals are generated without external modulator and erbium-doped fiber

The instantaneous evolutions of the molten pool and plasmas during the pulse fiber laser welding of pure zirconium (Zr) under different high pressure environment were explored. Furthermore, the mechanism and influence law of the increase of the pressure on the weld penetration of pure Zr were analyzed. The result indicated that the weld penetration of pure Zr significantly reduced with the ambient

Super-resolution fluorescence microscopy plays an important role in the field of biological science with a tremendous potential, for the capability of observing living cells in real time. Numerous super-resolution methods have been developed to surpass the diffraction limit in recent years. Two-photon structured illumination microscopy (TPSIM) combines structured illumination microscopy (SIM) with

A resonator–qubit system consisting of three resonators and two qubits is shown to enable a perfect swap and a faithful transfer of arbitrary unknown quantum states of photons, providing a much-needed building block for quantum information processing and quantum communication.

Color coding greatly improves the measurement efficiency of structured light three-dimensional(3D) measurement system. However, chromatic aberration (CA) reduces the measurement accuracy of the system. In this study, the lateral chromatic aberration (LCA) of camera and projector is analyzed by experiments, and the optimization model of LCA is studied according to the analysis results. Based on the

We propose a new kind of Bessel beams, namely the segmented-phase high-order Bessel beams (SHBBs). Compared to the traditional high-order Bessel beams, the proposed beams have segmented helical phases instead of the integer topological-charge helical phases. As a result, the phase segments of the beams may carry orbital angular momenta of different topological charges. The simulation and experimental

Accurate identification of the shape and texture properties of cervical cell nuclei and cytoplasm in the pap smear test is crucial for the diagnosis of cervical cancer. Fast and high-precision polarization modulation in the Polarization Indirect Microscopic Imaging (PIMI) is achieved by utilizing a liquid crystal polarization rotator. Imaging results of cervical cells show that the PIMI method can

Optical waveguide amplifiers based on NaYF4 : Er3+, Yb3+ nanocrystals prepared by high-temperature thermal decomposition method with forward and backward pump schemes are designed. The gain characteristics of the two schemes are compared through simulation and experiment. For an input signal power of 0.1 mW and a pump power of 270 mW, relative gains of 5 and 5.6 dB are obtained by forward and backward

A laser beam carrying object information will become a random speckle pattern as it propagates through a hollow core fiber (HCF) of large inner diameter. We propose and experimentally demonstrate a technique that employs the convolutional neural network (CNN), which is one type of deep learning, for image reconstruction from the random speckle pattern. In the experimental demonstration, 4000 speckle

This paper reports a study of Optoelectronic Oscillator (OEO) using dual parallel dynamic control band pass filter (BPF). A new arrangement has been proposed where the static BPF is replaced by a dual dynamic control BPF under the influence of angle modulated synchronizing signal. The governing equation of the proposed system has been derived and the steady state conditions are audited. A considerable

Using the simultaneous assistance of the water-based ultrasonic vibrations and a side-loaded magnetic field, the transient real-time observation with the metallurgical examination were carried out for laser percussion drilling in the stainless steel sheets, which aimed for demonstrating the effect of the magnetic-ultrasonic assistance on the hole-drilling process with metallurgical alteration characteristics

We present single-exposure SNR-enhanced holography (SE-SEH). In SE-SEH, three beams with different wavelengths simultaneously illuminate the sample (particle field) with varied oblique directions, a color CCD records the light transmitted through the sample. The information included in each color channel is retrieved by analyzing the RGB channels, and processed with a chromatic aberration corrected

Topological photonic crystals (TPC) can effectively suppress the backscattering from defects and achieve unidirectional transmission with high forward transmittance, thus becoming a promising candidate in integrated photonic chip applications. Among different TPCs, the valley photonic crystals (VPCs) based on quantum valley Hall effect (QVHE) originating from valley-dependent spin-split bulk bands