Optical Control Method Research Articles

A novel optical orthogonality control approach based on noise propagation and its application in spin-exchange relaxation-free co-magnetometers

This paper presents a non-destructive optical orthogonality control method based on adaptive gradient descent for spin-exchange relaxation-free co-magnetometers (SERFCM). The spin-exchange optical pumping technique serves as the foundation of SERFCM measurement. Analyzing the impact of pump power fluctuation on the transverse polarizability of alkali metal atoms in the presence of non-orthogonal beams, considering stochastic noise propagation, is addressed. Subsequently, an optical orthogonal calibration scheme is proposed. Leveraging the proposed orthogonal calibration scheme, an adaptive gradient descent method based on the reference model is formulated, and simulation validates its effectiveness in addressing the rapid online optimization control of SERFCM optical quadrature. Experimental results indicate that the proposed optical orthogonal calibration scheme offers higher accuracy, with the proposed optical orthogonal control algorithm saving 34% of the time compared to the traditional algorithm. Finally, the stability of SERFCM is evaluated using Allan variance, demonstrating that the adjusted SERFCM enhances short-term stability by 84% at around 1s and long-term stability by 639% at around 300s.

Research on control and management of smart grid optical network based on optical transmission control Protocol (OTN) technology

Smart grids can improve the operational efficiency and reliability of power systems, and optical transmission control protocol (OTN) technology is widely used in the field of power communication. This article focuses on the control and management of smart grid optical networks, aiming to achieve efficient control and management of smart grid optical networks through OTN technology. This article proposes a smart grid OTN management system based on Optical Transmission Control Protocol (OTN) technology. This system achieves the management and optimization of power OTN business by researching functions such as container management and service orchestration, pod and physical node management, application and cluster status monitoring, application logs and cluster logs. In this system, the sources of data are very rich. Data can be obtained from databases, file streams and Flow network. This can ensure that the system receives comprehensive data support for better business analysis and decision-making. This article further studies the optimization methods of optical network control for power OTN services to improve network reliability and reduce risk levels. The experimental results indicate that the use of OTN technology can improve the operational efficiency and reliability of the smart grid, and achieve remote monitoring and control of the smart grid.

Programmable meta-holography dynamics enabled by grating-modulation

Towards next-generation intelligent display devices, it is urgent to find a cheap and convenient dynamic optical control method. Conventional gratings are widely used as cheap diffractive elements due to their effective optical control capabilities. However, they are limited within multi-function or complex optical modulation due to the lack of accurate control of the amplitude/phase at pixel-level. Here, a metasurface-assisted grating-modulation system is originally proposed to achieve switchable multi-fold meta-holographic dynamics. By incorporating metasurfaces with traditional gratings and tuning their relative coupling positions, the modulation system gains the optical modulation capability to realize complex optical functionalities. Specifically, by varying the grating periods/positions relative to the metasurface, 2–8 holographic image channels are programmed to be dynamically exhibited and switched. The proposed metasurface-assisted grating-modulation approach enjoys cost-effective convenience, strong encoding freedom, and facile operation, which promises programmable optical displays, optical sensors, optical information encryption/storage, etc.

Optical interference phase control method with single photodetector for interference lithography.

This study designs an optical phase control method for interference lithography system accompanied with severe disturbance. The system, which is designed based on the exponential reaching law of sliding mode control(SMCE), could adjust the interference phase with single photodetector. The model of system is derived and then the stability is proved through Lyapunov theorem. This paper also analyzes the behavior of the system under different reference voltages of photodetector. Both theoretical analysis and simulation experiment results suggest that this method can non-periodically achieve interference phase control with single photodetector by the switching module. Finally, the experimental device is set up, and the superiority of the SMCE method in transient response time and disturbance-resisting ability is demonstrated compared with the proportional-integral-derivative(PID) method.

Cascaded subarray design and control method for power efficient, thermal crosstalk optimized optical phased array.

Thermo-optic phase shifters (TOPSs) are commonly used in large-scale silicon photonic integrated optical phased arrays (OPAs). However, fast-response TOPSs consume relatively high power; the elevated temperature floor in the dense region of the TOPSs introduces thermal crosstalk between optical paths, which undermines the control accuracy. We propose a combined method that involves subarray design in the optical power distribution network and array control method to predict, optimize, and redistribute the phase shifts and mitigates thermal crosstalk. Thermal simulations and an array control method for generic OPA models are discussed. A silicon photonic chip prototype of a 4 × 4 OPA with three-level cascaded subarrays is fabricated to demonstrate the proposed method. The experimental and statistical results show that the method effectively reduces the average total power consumption by 31%, the maximum local temperature by 18.4%, and the thermal crosstalk within the OPA.

Natural exceptional points in the excitation spectrum of a light–matter system

In this work, we observe natural exceptional points in the excitation spectrum of an exciton–polariton system by optically tuning the light–matter interactions. The observed exceptional points do not require any spatial or polarization degrees of freedom and result solely from the transition from weak to strong light–matter coupling. It was demonstrated that they do not coincide with the threshold for photon lasing, confirming previous theoretical predictions [Phys. Rev. Lett. 122, 185301 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.185301, Optica 7, 1015 (2020)OPTIC82334-253610.1364/OPTICA.397378]. Using a technique where a strong coherent laser pump induces up-converted excitations, we encircle the exceptional point in the parameter space of coupling strength and particle momentum. Our method of local optical control of light–matter coupling paves the way to the investigation of fundamental phenomena, including dissipative phase transitions and non-Hermitian topological states.

Мобильный спелеологический параллельный робот с пространственной тактильной системой распознавания контактной поверхности

The paper considers the problem of conducting speleological studies of natural and artificial caves, including channels of the underground rivers, as well as various mine workings in dangerous or inaccessible conditions for a speleologist. In this case, external environment of the objects under study could turn out to be opaque for optical, radio, ultrasonic and other physical methods of monitoring the inner surface, for example, due to partial or complete flooding of the object with water with inhomogeneous suspensions. A solution to the problem is proposed by robotizing the research using a mobile speleological parallel robot (MSPR) with a spatial tactile system for identification of the contact surface. MSPR is created in the form of an active octahedral structure, which edges are rods with linear drives. The rod ends are pivotally connected to the corresponding vertices of the active octahedral structure ensuring its geometric invariability when the linear drives are turned off. As a result, MSPR is able to carry out contact (tactile) mapping of the inner surface under study regardless of the external environment transparency and its geodetic binding to the base coordinate system with visualization in the form of histograms. At the same time, MSPR is able to self-move along the internal surfaces regardless of their spatial orientation. MSPR and its functionalities are described, one of which is the ability to build the 3D histograms of the surrounding space bind to the base (inertial) coordinate system through the mechanical contact. The tactile system of identifying the contact surface makes it possible not only to move the MSPR, but also to tactilely monitor in the external environment that is opaque for optical, radio, ultrasonic and other physical control methods. MSPR allows robotizing speleological research in dangerous, hard-to-reach and inaccessible places for a speleologist, as well as to carry out rescue operations and ensure delivery of the required cargo.

Optimization two-qubit quantum gate by two optical control methods in molecular pendular states

Implementation of quantum gates are important for quantum computations in physical system made of polar molecules. We investigate the feasibility of implementing gates based on pendular states of the molecular system by two different quantum optical control methods. Firstly, the Multi-Target optimal control theory and the Multi-Constraint optimal control theory are described for optimizing control fields and accomplish the optimization of quantum gates. Numerical results show that the controlled NOT gate (CNOT) can be realized under the control of above methods with high fidelities (0.975 and 0.999) respectively. In addition, in order to examine the dependence of the fidelity on energy difference in the same molecular system, the SWAP gate in the molecular system is also optimized with high fidelity (0.999) by the Multi-Constraint optimal control theory with the zero-area and constant-fluence constraints.

Анализ качества меандра фольгового электронагревателя космического назначения, изготовленного с использованием лазерного излучения

The article presents a brief review of the photolithographic technology features used in manufacture of foil electric heaters for spacecraft. Potential advantages of laser technology for the foil electric heater formation are demonstrated. Using laser radiation, a full-fledged meander was manufactured from constantan foil on flexible substrate of aramid fabric impregnated with the EP-730 varnish as a blank for a foil electric heater of the spacecraft thermal control system. The degree of constantan evaporation between the current conductive tracks, as well as integrity and dielectric properties of the substrate, were evaluated. Results of the obtained samples study by the methods of spectral analysis, visual and optical control and measurement of the insulation resistance are provided. Conclusions present an assessment of advantages in using laser processing in the heating element formation, namely, reduction in the number of technological operations, decrease in labor intensity, increase in accuracy of the design geometry and improvement in the personnel labor protection conditions.

AUTOMATIC STREET LIGHT CONTROL AND MONITORING SYSTEM

Street lighting is one of the important parts of a city’s infrastructure where the main function is to illuminate the city’s streets during dark hours of the day. Previously, the number of streets in the town and city were less. So, the street lamps were relatively simple but with the development of urbanization, the number of streets increased rapidly with high traffic density. There are several factors needed to be considered in order to design a good street lighting system such as night-time safety for community members and road users, provide public lighting at low cost and the reduction of light pollution. Initially, the street lamps were controlled manually where a control switch is set in each of the street lamps. It is called first generation of the original street light. After that, another method that was been used was optical control method. This method uses high pressure sodium lamp in their system. It can be seen that this method is widely used in the country nowadays. This method operates by setting up an optical control circuit. It lights up automatically at dusk and turns off automatically after dawn in the morning. The system utilizes the latest technology for the sources of light as LED Lamps instead of generally used street lamps such as High Pressure Sodium Lamps, etc. The LED technology is preferred as it offers several advantages over other traditional technologies. The application is designed in such a way that we place light sensors in all street light circuits, which is responsible to switch on and off automatically. Once the lights are switched on current sensors placed at every street light circuits are responsible to report problem status to the centralized system with help of GSM module attached with the circuit The system described can effectively save energy by reducing the power consumption as per requirement. Since this is a sensor based system, so it is self-controlled and automated system. The system is also flexible for any modification or further expansion such as interfacing of new sensors, connecting surveillance camera for the security purpose, etc. This project of Smart Street Light System is a cost effective, practical, eco-friendly and the safest way to save energy.

Optical Control of Phosphoinositide Binding: Rapid Activation of Subcellular Protein Translocation and Cell Signaling.

Cells utilize protein translocation to specific compartments for spatial and temporal regulation of protein activity, in particular in the context of signaling processes. Protein recognition and binding to various subcellular membranes is mediated by a network of phosphatidylinositol phosphate (PIP) species bearing one or multiple phosphate moieties on the polar inositol head. Here, we report a new, highly efficient method for optical control of protein localization through the site-specific incorporation of a photocaged amino acid for steric and electrostatic disruption of inositol phosphate recognition and binding. We demonstrate general applicability of the approach by photocaging two unrelated proteins, sorting nexin 3 (SNX3) and the pleckstrin homology (PH) domain of phospholipase C delta 1 (PLCδ1), with two distinct PIP binding domains and distinct subcellular localizations. We have established the applicability of this methodology through its application to Son of Sevenless 2 (SOS2), a signaling protein involved in the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade. Upon fusing the photocaged plasma membrane-targeted construct PH-enhanced green fluorescent protein (EGFP), to the catalytic domain of SOS2, we demonstrated light-induced membrane localization of the construct resulting in fast and extensive activation of the ERK signaling pathway in NIH 3T3 cells. This approach can be readily extended to other proteins, with minimal protein engineering, and provides a method for acute optical control of protein translocation with rapid and complete activation.

High-Potential Test for Quality Control of Separator Defects in Battery Cell Production

Lithium-ion batteries are a key technology for electromobility; thus, quality control in cell production is a central aspect for the success of electric vehicles. The detection of defects and poor insulation behavior of the separator is essential for high-quality batteries. Optical quality control methods in cell production are unable to detect small but still relevant defects in the separator layer, e.g., pinholes or particle contaminations. This gap can be closed by executing high-potential testing to analyze the insulation performance of the electrically insulating separator layer in a pouch cell. Here, we present an experimental study to identify different separator defects on dry cell stacks on the basis of electric voltage stress and mechanical pressure. In addition, finite element modeling (FEM) is used to generate physical insights into the partial discharge by examining the defect structures and the corresponding electric fields, including topographical electrode roughness, impurity particles, and voids in the separator. The test results show that hard discharges are associated with significant separator defects. Based on the study, a voltage of 350 to 450 V and a pressure of 0.3 to 0.6 N/mm2 are identified as optimum ranges for the test methodology, resulting in failure detection rates of up to 85%.

A key bidirectional switching issue in optogenetics emulated with laser dyes to illustrate its mitigation using nonlinear optical tools

Conventionally, bidirectional optogenetic switches are controlled with linear excitation (e.g., monochromatic CW light), which has serious limitations when there is a spectral overlap between the “on” and “off” states of the switch. The spectral crosstalk lowers the selectivity of the photoactivation step, resulting in a moderate photoequilibrium value and a poor dynamic range for the switch. Using stimulated depletion quenching (SDQ), which is a nonlinear optical strategy similar to STED, we demonstrate enhanced photoactivation selectivity on one side of the switch, thus shifting the photoequilibrium beyond what is achievable with CW light. The discussion is built around Cph8 as a prototypical bidirectional optogenetic switch lacking complete photoreversibility upon CW excitation because of the spectral crosstalk. We use two fluorescent dyes as analogues to emulate the key spectral feature of the on and off states of Cph8; in this way, we focus on the initial photoactivation step and abstract from the complicated subsequent dynamics. By applying SDQ to a mixture of the dyes, we enhance the selectivity of the photoactivation beyond the linear regime. Increased selectivity of the photoactivation step via nonlinear optical techniques should translate into an improved dynamic range for a broad variety of bidirectional switches. These experiments provide a basis to further expand the foundations for non-conventional optical control methods of biological switching.

Method of rapid assessment of sulfide sulfur content in host rocks

The aim of the research is to assess the possibility of using the energy-dispersive X-ray fluorescence method directly at the stoping operation site. To meet this objective, a hand-held X-ray fluorescence spectrometer of the expert class of the NITON XL2 brand was selected. This will solve the problem of developing an express method for assessing the explosive and fire-hazardous properties of sulfur-containing or pyrite-containing ore. The development of the method is dictated by the need for operational control of the dust explosion hazard of sulfur-containing rocks and the assessment of their tendency to spontaneous combustion and also the possibility of making amendments to the development process of complex heterogeneous host rocks. Visual and optical control methods were used as an auxiliary method. In the process of developing the express method, both express analyses were carried out directly at the face bottom, and monolithic large-sized pieces of mined rock mass and also additional laboratory studies of previously studied samples of these rocks dispersed to a size of less than 100 microns were performed. The obtained results allowed to draw a number of conclusions about the expediency of using the X-ray fluorescence express method and suggest ways to use it directly in the stoping face.

Opto-valleytronics in the 2D van der Waals heterostructure

The development of information processing devices with minimum carbon emission is crucial in this information age. One of the approaches to tackle this challenge is by using valleys (local extremum points in the momentum space) to encode the information instead of charges. The valley information in some material such as monolayer transition metal dichalcogenide (TMD) can be controlled by using circularly polarized light. This opens a new field called opto-valleytronics. In this article, we first review the valley physics in monolayer TMD and two-dimensional (2D) heterostructure composed of monolayer TMD and other materials. Such 2D heterostructure has been shown to exhibit interesting phenomena such as interlayer exciton, magnetic proximity effect, and spin-orbit proximity effect, which is beneficial for opto-valleytronics application. We then review some of the optical valley control methods that have been used in the monolayer TMD and the 2D heterostructure. Finally, a summary and outlook of the 2D heterostructure opto-valleytronics are given.

Polariton MultiMode Interferometer Controlled by Optical Stark Shift in WS2 Microcavity

Applications based on the formation of exciton polariton in microcavities provide new avenues for the realization of low-energy consumption and ultrafast devices in areas of photo-electronic and quantum information. Here, we propose a way to design polaritonic multi-mode interferometers in a WS2 microcavity by an all optical control method. The interference phenomenon of polariton is controlled by the well-known optical Stark effect. The optical Stark light changes dispersion (e.g., effective refractive index) of the illuminated region, and generates a waveguide region therein, thus supporting different guided modes of polariton. Multi-mode interference of polariton is then guided by changing the beam pattern or intensity of the Stark light. This proposed method is then theoretically analyzed and proved via effective refractive index calculation and eigenmode analysis of plane waveguide.

On-Resin Passerini Reaction toward C-Terminal Photocaged Peptides.

An on-resin, three-component Passerini reaction was developed to synthesize C-terminal photocaged peptides. Highly compatible with conventional Fmoc SPPS, this reaction produces peptides with a C-terminal o-amido-6-nitroveratryl (αANV) ester in one pot with conserved chirality. Under physiological conditions, the C-terminal αANV ester rapidly photolyzed to revert to carboxylate, offering a convenient method for optical control of cellular signals by modulating the C-terminal carboxylate.

Optical control method of fuel atomization in combustion chambers using high-speed video recording

The article gives the description of the optical method and the high-speed video registration test bed for determining the parameters of fuel atomization in atmospheric conditions. The diagram and operating principle of the test bed are described. The experimental results of the jet parameters when atomizing rapeseed oil and diesel fuel are presented.

The role of hydroxyl ions in the evolution of optical nonlinearity of CuO: a Z scan study

The method of optical nonlinearity control is significant because of its wide range of application in the design and fabrication of optical devices. The paper reports the role of hydroxyl (OH) ions in the evolution of optical nonlinearity of copper oxide (CuO) through Z scan technique by preparing its nanofluid. The powdered CuO formed through the ageing of copper hydroxide (Cu(OH)2) is subjected to structural and morphological characterizations. The Field emission scanning electron microscopic (FESEM) analysis shows a morphological modification from rod to flakes. The x-ray diffraction (XRD) study carried out helps not only in understanding the formation of CuO but also in estimating the variation of particle size, dislocation density and morphology index with ageing. The Z scan study suggests the nonlinear refractive index n2 of CuO be negative and exhibit a fourth order polynomial variation with ageing irrespective of the laser power. The value of n2 is found to decrease with the laser power and increase with the linear absorption coefficient. The Fourier transform infrared (FTIR) spectroscopic analysis reveals the structural modifications in the evolution of CuO from Cu(OH)2. The value of n2 is found to exhibit an inverse relation with the amount of OH groups that is exemplified through the evolution of CuO from Cu(OH)2 upon ageing. The study is significant from the point of view of designing materials with tailored nonlinear optical properties.

Tuning the coupling between quantum dot and microdisk with photonic crystal nanobeam cavity.

Strong coupling between solid-state quantum emitters and microcavities paves the way for optical coherent manipulation of quantum state and provides opportunities for quantum information processing. However, it is still a challenge to realize strong coupling due to the spectral and spatial mismatch between quantum emitters and cavity modes. Here, we propose a scheme to tune the coupling between a single QD and a microdisk with 1D photonic crystal nanobeam cavity. Based on Finite-Difference Time-Domain (FDTD) method and Green's function expression for the evolution operator, we demonstrate that QDs with emission wavelengths +1.27 nm and -1.44 nm detuned from the bare microdisk mode can be coupled to the system strongly. Particularly, we observe simultaneous coupling between QD and two cavity supermodes, which enriches the optical coherent control methods of quantum states. By adjusting the distance between the two cavities, we can control the coupling between QD and photons. Furthermore, benefiting from the natural integration of nanobeam cavity to waveguide, such a system provides advantages for implementing quantum internet.