Ion beam finishing techniques of aluminium mirrors have a high potential to meet the increasing demands on applications of high-performance mirror devices for visible and ultraviolet spectral range. Reactively driven ion beam machining using oxygen and nitrogen gases enables the direct figure error correction up to 1 μm machining depth while preserving the initial roughness. However, the periodic turning

Quantitative prediction of the smoothing of mid-spatial frequency errors (MSFE) is urgently needed to realize process guidance for computer controlled optical surfacing (CCOS) rather than a qualitative analysis of the processing results. Consequently, a predictable time-dependent model combining process parameters and an error decreasing factor (EDF) were presented in this paper. The basic smoothing

Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance

In this work a 3D flame reconstruction is performed from a 2D projection of the hot gases of a combustion flame. The projection is obtained using an optical schlieren technique. In this technique, a schlieren image is integrated linearly to obtain the hot gases, and then, a temperature field. Each row of the matrix representing the temperature distribution is fitted with a specific function, and its

An amendment to this paper has been published and can be accessed via the original article.

The research presented in this paper is focused on the link between manufacturing parameters and the resulting mid-spatial frequency error in the manufacturing process of precision optics. The goal is to understand the generation mechanisms of mid-spatial frequency errors and avoid their appearance in the manufacturing process. Also, a simulation which is able to predict the resulting mid-spatial frequency

We theoretically exploit the shortcuts to adiabaticity (STA) technique in Hermitian and non-Hermitian quantum systems to realize the maximum coherence and beam splitting by eliminating the nonadiabatic coupling. Compared with the conventional adiabatic passage (AP) technique with the Gaussian and Allen-Eberly schemes, the operation time can be significantly shortened by three order using STA technique

The theoretical analysis of transverse electric surface waves in ferrite medium surrounded by isotropic plasma layers is presented in this manuscript. Maxwell’s equations in differential form are used, and we impose the boundary conditions to acquire the dispersion relation to formulate the proposed structure. The influence of number density, separation distance between the layers of plasma, and dielectric

Today digital holographic interferometry (DHI) is considered a modern full-field non-destructive technique that allows generating 3D quantitative data of a wide variety of specimens. There are diverse optical setups for DHI that enable the study of specimens in static and dynamic conditions: it is a viable alternative to characterize a wide diversity of parameters in the micro and macro world by conducting

The sensor is designed by combination of photonic crystal fiber (PCF) and fiber Bragg grating (FBG), which is based on Sagnac interferometer to measure temperature and stress simultaneously in changing environment. The interference between two parameters is avoided by cascading two wavelength moving reverse components in this sensor system. When the PCF is connected with FBG or not, the linearity of

Despite metallic plasmonic excitations can enhance the performance of ultra-thin solar cells however these so-called plasmonic solar cells suffer from a large resistive (Ohmic) loss caused by metallic elements. In this work, we report on a new design that uses graphene nanoribbons (GNRs) in a two-dimensional (2D) grating form at the top of the semiconductor-on-insulator (SOI) solar cells aimed to reduce

Signal buffering services such as contention resolution and congestion avoidance are essential in optical packet switching networks. In this paper, an optical memory scheme based on spectral amplitude coding (SAC) and complementary code keying (CCK) is proposed to increase the buffer capacity. CCK is applied to packet buffering by selecting an available code set and encoding the payload bits with either

The full-chain system performance characterization is very important for the optimization design of an integral imaging three-dimensional (3D) display system. In this paper, the acquisition and display processes of 3D scene will be treated as a complete light field information transmission process. The full-chain performance characterization model of an integral imaging 3D display system is established

For visible light communication (VLC), the light signals are transmitted without optical fibers or any sort of wave-guiding. Due to the inherent broadcast nature, physical-layer security emerges as a promising method to protect information delivery from eavesdropping. As for the secrecy capacity of VLC channel, there exist two features. In one way, the limited optical power makes the common capacity

An optical 32QAM-OFDM-PON system with different numbers of sub-carriers using discrete multitone (DMT) modulation and demodulation is designed and demonstrated by experiment. Electron-optic generation, directly photoelectric detection, and electrical self-mixing reception of 32QAM-OFDM downstream signals are achieved. 5Gb/s 32QAM-OFDM downlink signals with different numbers of sub-carriers are successfully

In this paper, a method of how to construct a freeform surface directly in an off-axis reflective image system is proposed. The method includes both the seed curve extension algorithm and simulated annealing algorithm. Firstly, the sample points on the unkown freeform surface were be obtained quickly by the seed curve extension algorithm. Then the continuity of the freeform surface is evaluated by

Realization of Fano resonance in plasmonic oligomers is often exploited to design efficient plasmonic substrates for surface-enhanced coherent anti-Stokes Raman scattering. Disk-type Fano-resonant plasmonic oligomers are widely used to enhance the Raman signal of the probe material. Generally, hot spots are generated in those oligomers at different spatial locations at different wavelengths and only

Focusing grating couplers for the excitation of the fundamental transverse-magnetic (TM) mode in integrated silicon photonic waveguides are designed and characterized under the boundary conditions of a photonic BiCMOS foundry. Two types of waveguide geometries are considered – a nanowire and a rib waveguide. Wafer-scale experimental results for nanowire TM grating couplers are in excellent agreement

In the last two decades there has been growing interest in silicon photonics and in the possibility to integrate new materials to overcome the silicon intrinsic limitations. Erbium has represented a viable solution for the realization of light sources at telecommunications wavelengths opening the path to the investigation of various photonic devices based on rare earth. In this work we investigate

Technical advances in instrument manufacturing have promoted the miniaturization and cost reduction of portable NIR spectrometers. The price of a device is now affordable to ordinary consumers, which might promotes the application of NIRS in real scenarios. Generally, the portable spectrometers have a lower spectral resolution and a narrower spectral region compared with the benchtop ones. Whether

We present a detailed frequency noise analysis of a feedforward scheme used to faithfully transfer the spectral properties of an individual line of an optical frequency comb spectrum to a single-mode laser and in this way indirectly amplify it, which is applicable to any arbitrary comb mode spacing. In contrast to previously reported implementation of the feedforward method for a similar purpose, we

In some active optics system, the influence function, which is the surface deformation ability of an actuator, is measured by directly detecting the mirror surface using an interferometer and the surface correction of the primary mirror is done using the Shack-Hartmann (S-H) sensor. However, if the wavefronts of the interferometer and the S-H sensor have an obvious rotation, a large error will be introduced

A round robin comparison of freeform form measurements was carried out by the project partners and stakeholders of a European metrology research project. Altogether six measuring instruments were considered: five different (pointwise and areal) optical devices and one tactile device. Three optical freeform surfaces were used for the comparison measurements, where two specimens were measured by five

Stripe non-uniformity severely affects the quality of infrared images. It is challenging to remove stripe noise in low-texture images without blurring the details. We propose a single-frame image stripe correction algorithm that removes infrared noise while preserving image details. Firstly, wavelet transform is used for multi-scale analysis of the image. At the same time, Total variation model is

Modern optical multi-camera systems require integrating many camera modules in a small volume. A new space-saving concept for such imaging systems is presented, based on intersecting optical paths that utilize one or more common elements for the respective optical paths. The principles for the optimization for such systems is examined, providing the theory for geometric optimization constraints. These

Precision and ultra-precision surfaces are crucial for many products – quality optics, joint & cranial implants, turbine blades, and industrial moulds & dies, to name a few. Automation in this context is distinct from standard procedures in industry, where the identical sequence of operations can be repeated over and over again. Ultraprecision tolerances may be tens to hundreds of times tighter, and

A special periodic spectral fluctuation is observed during the study of a fibered high sensitivity optical feedback cavity-enhanced absorption spectroscopy (OF-CEAS) for the measurement of trace gas. This spectral fluctuation is different from some phenomenon observed in former OF-CEAS which contain a resonant cavity with V-shaped configuration, such as the etalon effect and the spectral ripple effect

We report on achieving tuned single mode operation of a multimode semiconductor laser by coupling it to a very-short external cavity with selective feedback. We show that the induced uniform feedback light from the very-short external cavity can induce single-mode oscillation over a broad range of optical feedback. Then by applying selective external to the optimum settings of the single-mode oscillation

Palm oil is one of the most useful vegetable available. Sudan IV dye is used as hue enhancer in palm oil despite the ban as food colorant due to its carcinogenicity and mutagenicity by the International Agency for Research on Cancer (IARC). Surface enhanced Raman spectroscopy (SERS) coupled with chemometric methods was applied to detect the presence of Sudan IV in some edible palm oil samples. We studied

Phase measuring deflectometry is a highly precise and full field metrology technique for specular surfaces based on the distortion of known reference patterns observed as a reflection at the surface under test. Typically, liquid crystal displays are employed to provide the required patterns. Due to a lack of research, these displays are used without sufficient calibration. In this work, we present

In this work, a nanostructured guided-mode resonance filter matrix with high transmission efficiency and narrow bandwidth is demonstrated. The developed nano-filter arrays have various usages, e.g., combined with the CMOS image sensors to realize compact spectrometers for biomedical sensing applications. In order to optimize the filter performance, the spectral responses of filters with different structural

In order to remove mid-spatial frequency errors on aspheric and freeform surfaces, we have developed an aspheric smoothing tool which, unusually, is rigid. This has been proved feasible in the special case where the abrasive grit size exceeds the aspheric misfit, providing a cushion. Firstly, experimental parameters were derived from simulation of Influence Functions regarding misfit between the tool

The behavior of the light field near the beam waist has attracted considerable attention due to the studies of the light spin-orbit interaction: it’s manifestation as well as potential applications. Similarly, the light beam diffraction can reveal new light particularities. We have studied the far-field diffraction of a Gaussian beam by a half-plane edge placed near the beam waist. We have solved numerically

Interface SDN network with Optical network to enhance the capability of current optical network capability to achieve high data rate support to fulfilled 5G and Internet of things (IoT) backbone capacity requirement. We use the proposed SDON design architecture based on Software defined networking and do the performance analysis so that proposed work can provide the backbone for current 5G and IoT

Ultrafast lasers continue to be at the forefront of many scientific breakthroughs and technological achievements and progress in the performance of these systems continue to open doors in many new and exciting interdisciplinary fields. In particular, in the last decade, the average power of ultrafast lasers has seen a significant increase, opening up exciting new perspectives. Among the different technologies

In this contribution, we investigate hybrid single vision spectacle lenses (SVSLs) consisting of holographic optical elements (HOEs) embedded into a refractive lens. We evaluate the performance of two examples of hybrid SVSLs in terms of their distributions of spherical error (SPH error), astigmatic error (AST error) and transverse chromatic error (CE) over the lens surface, simulating the optical

This paper displays numerical simulation for bright and dark optical solitons that emerge from Fokas-Lenells equation which is studied in the context of dispersive solitons in polarization-preserving fibers. The Laplace-Adomian decomposition scheme is the numerical tool adopted in the paper. The numerical results, for bright and dark solitons, are expository and therefore supplement the analytical

In this work, two photo-structuring processes, photo induced spontaneous surface structuring (PSSP) and photo induced supramolecular chirality (PSC) are applied to high-performance azo polymers. We demonstrate higher induced optical rotation than described previously in other reports and show that self-organized surface morphologies are not detrimental for the formation of PSC.

The influence of incident angle and aberration of the microlens array on the optical efficiency in pico-projector is analyzed. By modifying the relevant parameters, a method to optimize the optical efficiency and uniformity of the illumination system is proposed. By changing the profile of the freeform double lens used for the concentrator of LED source, the incident angle can be reduced, thus the

A boundary value problem involving the scattering of electromagnetic waves from a sphere of complex conjugate medium (CCM) is studied. The sphere is placed in free space. The source of excitation for the sphere in our case is a plane wave. Incident, scattered and transmitted fields are formulated. The unknown coefficients in the scattered and transmitted fields are found using boundary conditions.

Classical zoom lenses are based on movements of sub-modules along the optical axis. Generally, a constant image plane position requires at least one nonlinear sub-module movement. This nonlinearity poses a challenge for the mechanical implementation. Tuneable lenses can change their focal length without moving along the optical axis. This offers the possibility of small system lengths. Since the focal

For lighting applications demanding high brightness, a new type of LED-based light source has been developed, the high lumen density (HLD) source (luminance > 2·109 cd/m2). The performance can be improved further, among other things by optimizing the concentrator used as extraction optics. For this optimization, much insight is obtained by ray-tracing simulations. The efficiency can be improved by

Photonic crystal fiber Mach-Zehnder modal interferometers based on no adiabatic tapered fibers are perspective for bio-chemical sensing, since they have very high refractive index sensitivity and it is possible for them to use a very small quantity of investigated samples. To obtain a desirable sensitivity to a needed analyte, it was proposed to coat a sensing surface of the refractive index sensor

A strip-loaded slot waveguide is a waveguide platform allowing a large amount of degrees of freedom in terms of fabrication. Contrary to other waveguide types where the guiding layer has to be patterned, only the shape of the top layer, usually a polymer, dictates the response of this platform. We use the Finite Difference Time Domain method to study the field distribution and the modal behavior of

Interference signals in coherence scanning interferometry at high numerical apertures and narrow bandwidth illumination are spectrally broadened. This enables phase analysis within a spectral range much wider than the spectral distribution of the light emitted by the light source. Consequently, different surface features can be resolved depending on the wavelength used for phase analysis of the interference

Surface plasmon polaritons (SPPs) are electromagnetic waves that propagate at a metal-dielectric interface. Until recently, monochromatic, fully coherent SPPs have mainly been considered. We investigate by numerical simulations the generation and properties of polychromatic, partially coherent SPPs and their scattering from a nanostripe. We use both in-house and commercial codes. A standing SPP field

We report on an auxiliary field approach for solving nonlinear eigenvalue problems occurring in nano-optical systems with material dispersion. The material dispersion can be described by a rational function for the frequency-dependent permittivity, e.g., by a Drude-Lorentz model or a rational function fit to measured material data. The approach is applied to compute plasmonic resonances of a metallic

Raising the interest in remote chemical analysis, in particular through Raman and fluorescence spectroscopy, the opportunity of increasing the exposure represents an important step for an easier and more reliable spectrum analysis. However, the European directive 2006/25/EC defines the maximum permitted exposure (MPE) to artificial radiations according to exposure duration, wavelength, coherence of

Determining the relative ubiety between the camera and the laser projector in a line-structured light vision sensor is a classical yet important task. Typical calibration methods often confront problems, such as difficulty of producing the target precisely and introduction of perspective projection errors. In this work, a new calibration method based on a concentric circle feature is introduced. The

Optical information encryption technology has received extensive attention from researchers in recent years because of its advantages of parallel and high-speed processing capability, as well as the controllability of phase components. An encryption method for grayscale images with a pair of random phase masks based on gamma distribution in the gyrator domain is proposed. In this scheme, two random

Homogenizing properties of beam shaping diffusers illuminated with coherent laser light was studied with special regard on their use in vision applications. Two diffusers projecting circular pattern at different scattering angles (Thorlabs Engineered Diffuser™) were illuminated with different spatial intensity distribution (elliptical Gaussian, nearly flat-top and granular multimode fiber output, respectively)

Optimized dithering fringe pattern is a promising method for high-speed, high-accuracy three-dimensional shape measurement. The recently proposed dithering optimization technology optimizes the fringe quality in either phase domain or intensity domain according to their objective functions. Phase-based optimization is direct and effective, but it is sensitive to projector defocusing levels. Intensity-based

This paper shows how to suppress residual amplitude modulation (RAM) appeared in a commercial electro-optic modulator (EOM) to improve an iodine-frequency-stabilized laser diode (LD) using frequency modulation spectroscopy (FMS). Since the RAM of an EOM is affected by the temperature of the EOM, the DC-offset applied to the EOM and the polarization of the incident beam, it should easily fluctuate with

Many applications require liquids to efficiently wet required surfaces as it denotes better performance. The dynamics of pure and complex liquid is known to influence the spreading properties; however, this influence is less understood and solicits other measuring techniques to elucidate the grey area. In this work, we demonstrate the use of simple yet novel optical methods in the monitoring of liquid

A dual-camera structured light system consisting of two cameras and a projector has been widely researched in three-dimensional (3D) profilometry. A vital step in these systems is 3D calibration. Existing calibration methods are time-consuming and complicated because each camera-projector pair is calibrated separately. In this paper, an improved calibration method is proposed to decrease the calibration

In the fast 3D shape measurement, it is an important factor to use the least number of fringe patterns to get the wrapped phase and the wrapped phase is always required to be retrieved to absolute phase. But the process of phase unwrapping may affect the quality of absolute phase. Besides absolute phase retrieval is time-costing especially for high-speed 3D shape measurement. This paper proposes a

If structures of interest are hidden beneath turbid layers such as biological tissues, imaging becomes challenging, even impossible. However, if the point spread function of the system is known from the presence of a guide star, application of common deconvolution algorithms can be a convenient approach to reconstruct even heavily scrambled images. In this work, we present the severity of scattering

Using optical techniques for tissue diagnostics (so-called ‘optical biopsy’) has been a subject of extensive research for many years. Various groups have been exploring different spectral and/or imaging modalities (e.g. diffuse reflectance spectroscopy, autofluorescence, Raman spectroscopy, optical coherence tomography (OCT), polarized light microscopy, etc.) for biomedical applications. In this paper

Using phase-only liquid crystal spatial light modulator (LC-SLM) to generate random illumination is always used in phase-retrieval and single pixel imaging as it have high energy efficiency. While the methods were only used to generate monochromatic illumination. This paper aims to use LC-SLM generating the multi-spectral random illumination. The method requires only one SLM; multiple laser beams are

A diffractive spiral axicon can be used for the generation of a vortex beam with orbital angular momentum. The coaxial superposition of multiple vortices can generate a complex field with off-axis optical vortices. These fields are known as optical vortex lattices. In general, this superposition is done by the use of spatial light modulators. Discretization of the continuous spiral in radial and azimuthal