Optical Information Systems Research Articles

Tunable Single-Photon Emission with Wafer-Scale Plasmonic Array.

Bright, scalable, and deterministic single-photon emission (SPE) is essential for quantum optics, nanophotonics, and optical information systems. Recently, SPE from hexagonal boron nitride (h-BN) has attracted intense interest because it is optically active and stable at room temperature. Here, we demonstrate a tunable quantum emitter array in h-BN at room temperature by integrating a wafer-scale plasmonic array. The transient voltage electrophoretic deposition (EPD) reaction is developed to effectively enhance the filling of single-crystal nanometals in the designed patterns without aggregation, which ensures the fabricated array for tunable performances of these single-photon emitters. An enhancement of ∼500% of the SPE intensity of the h-BN emitter array is observed with a radiative quantum efficiency of up to 20% and a saturated count rate of more than 4.5 × 106 counts/s. These results suggest the integrated h-BN-plasmonic array as a promising platform for scalable and controllable SPE photonics at room temperature.

Mechanical-electric composite-driven transfer nanoimprint for anti-reflective optical diffuser

Optical diffusers are the core component of optical information systems; however, the difficulty in reducing reflection caused by its complex surface morphology severely restricts the performance of the application systems. This study proposed and demonstrated a mechanical-electric composite-driven transfer nanoimprint technique to develop an anti-reflective optical diffuser by imprinting subwavelength-tapered nanocones on the extremely uneven micro-concave surface of a diffuser. Successively loading optimized mechanical pressure and electric-field on the designed discretely-supported template, enough deformation facing the uneven substrate was generated, which was impossible in the single-factor driven nanoimprinting technology. Therefore, full contact was formed between the template and the irregular diffused surface containing tightly narrow and deep micro-concave pits. To guarantee the high fidelity of the fabricated nanostructures, pre-curing and back-etching processes were implemented during transfer imprinting, which were different from the traditional process. Based on the full-contact mechanism and high fidelity process, an anti-reflective optical diffuser was developed through transfer imprinting of the sub-wavelength tapered nanocones on the surface of the diffuser. Experimental tests showed that the developed anti-reflective optical diffuser exhibited high spectral transmittance, high light intensity uniformity, and good durability.

Information systems with aperture compression

Subject of study. Variants of optical system designs with high aperture ratios at relatively low resolution are proposed. Aim of study. The study attempted to increase the energy of the optical signal received by optical information systems. Method. The proposed technical solutions are based on the design features of light-guide optical augmented reality systems with holographic mirrors utilized in reverse beam paths. Main results. The feasibility of adopting a light guide with a holographic mirror as an aperture compressor in optical systems, e.g., receiving free-space optical communication systems or laser rangefinders, is demonstrated. Variants of designs of optical systems with a light-guide aperture compressor operating with monochromatic radiation at several wavelengths and achromatic systems are presented. The use of a diffraction grating with an asymmetric groove profile instead of a holographic mirror is proposed in the last version of the optical system. Practical significance. The proposed system designs enable a significant increase in the intensity of the optical signal received by these systems by incorporating a non-detunable aperture compressor based on a light guide with a holographic mirror.

Intelligent electronic-optical sensor for information-measurement system of detection and identification of ground and aerodynamic objects

This work describes an original intelligent electronic-optical (laser) sensor (EOS) operating in the infrared range for systems that detect ground and aerodynamic objects and send control commands to the executive devices of portable information-measurement systems using specified algorithms. EOS proposed here differs from the known analogues by its ability of early detection and recognition of high-speed special machinery objects and small-sized unmanned aircrafts. EOS generates and sends probing optical pulses in the direction of a monitored high-speed object, processes the reflected location signal and retrieves the object coordinates and motion parameters. The classification features of the object are determined from the parameters of optical location signal used for object identification with the account the specific nature of optical location information systems.

Bidirectional Edge Asymmetric Light Transmission in Metal/Dielectric Device Based on Asymmetric Diffraction

Asymmetric light transmission (ALT) or optical diode-like nanodevices have attracted many research interests in recent years for its rosy potential application in all optical computing and information systems. In this work, we propose and numerically demonstrate a bidirectional edge asymmetric light transmission (BE-ALT) device, which is composed by the easy-processing metal/dielectric cylinders arranged periodically on glass substrate. The ALT effect in the proposed BE-ALT device shows a saltation at one critical wavelength, i.e., the asymmetric subtraction owns different signs for the wavelength larger and smaller than the critical wavelength. The asymmetric subtraction designed in this work changes dramatically from − 60% to + 80% at around 600 nm, which can be effectively manipulated by applying different structure parameters. The underlying physical mechanism has been investigated systematically, including the asymmetric diffraction effect, localized surface plasmonic resonance (LSPR), and the waveguide mode (WGM). Our designed BE-ALT device provides a new choice for the practical applications of ALT effect.

Approbation of the Laser Doppler Anemometer Lad-08 on the Secondary Standard Test Rig for Air Flow Speed

In the field of fundamental metrology and ensuring the unity of measuring instruments, the role of optical information methods, systems and technologies of non-contact diagnostics of dynamic processes is extremely relevant. The profiles of the axial velocity component were measured in the working section of the secondary standard test rig for air flow speed. The flow kinematics inside the working section is studied using a laser Doppler anemometer (LDA) with an adaptive temporal selection of the velocity vector (LAD-08).

Broadband integrated optical modulators: achievements and prospects

Broadband integrated optical modulators are key elements of modern optical information systems. The three main technological material platforms for their manufacture are considered: lithium niobate, III–V semiconductors, and silicon. Progress achieved in the development of integrated optical modulators is analyzed, and the main parameters of modulators obtained for various materials are compared with requirements for practical applications. Directions in the further development of the technology of modulators related to new problems in optical information systems are discussed.

Design and characterization of Eu2+-doped Ba4Si6O16 photostimulated phosphor for optical information storage

Novel persistent luminescence (PersL) phosphors are emerging as potential candidates for up-to-data information storage devices owing to its large memory capacity, low cost, and rewritable capability. In this study, a novel photostimulated luminescence (PSL) phosphor was successfully developed through co-doping Eu2+ and La3+ ions in Ba4Si6O16 (BSO) host. Firstly, the crystal structure, photoluminescence (PL), and PL excitation (PLE) of BSO:xEu2+ were studied systematically. Under the UV light source irradiation, the as-prepared BSO:0.02Eu2+ sample exhibits the best PersL decay property. Secondly, by applying the strategy of trap depth engineering, outstanding PersL performance is observed when La3+ ions were introduced into BSO:0.02Eu2+ as well. Moreover, the trap distribution and dynamics of electron motion in BSO: Eu2+, La3+ are characterized using methods of thermoluminescence spectra. Finally, verified by 980/808 nm photostimulation, BSO: Eu2+, La3+ shows promising application in optical information systems with a good optical storage capacity. In addition, based on the analysis of experiment and theoretical calculation results, a tentative energy level schematic is proposed to illustrate the mechanism of PersL and PSL in BSO:0.02Eu2+, La3+.

Quantum nonlinear light emission in metamaterials: broadband Purcell enhancement of parametric downconversion

Single-photon and correlated two-photon sources are important elements for optical information systems. Nonlinear downconversion light sources are robust and stable emitters of single photons and entangled photon pairs. However, the rate of downconverted light emission, dictated by the properties of low-symmetry nonlinear crystals, is typically very small, leading to significant constraints in device design and integration. In this Letter, we study principles of spontaneous emission control (i.e., the Purcell effect) generalized to describe the enhancement of nonlinear generation of quantum light through spontaneous parametric downconversion. We develop a theoretical framework based on eigenmode analysis to study quantum nonlinear emission in a general anisotropic, dispersive, and lossy media. Our theory provides an unprecedented insight into the emission process. We find that spontaneous parametric downconversion in a media with hyperbolic dispersion is broadband and phase-mismatch-free. We further predict a significant enhancement of the downconverted emission rate in experimentally realistic nanostructures. Our theoretical formalism and approach to Purcell enhancement of nonlinear optical processes provides a framework for description of quantum nonlinear optical phenomena in complex nanophotonic structures.

PsiQuaSP\u2013A library for efficient computation of symmetric open quantum systems

In a recent publication we showed that permutation symmetry reduces the numerical complexity of Lindblad quantum master equations for identical multi-level systems from exponential to polynomial scaling. This is important for open system dynamics including realistic system bath interactions and dephasing in, for instance, the Dicke model, multi-Λ system setups etc. Here we present an object-oriented C++ library that allows to setup and solve arbitrary quantum optical Lindblad master equations, especially those that are permutationally symmetric in the multi-level systems. PsiQuaSP (Permutation symmetry for identical Quantum Systems Package) uses the PETSc package for sparse linear algebra methods and differential equations as basis. The aim of PsiQuaSP is to provide flexible, storage efficient and scalable code while being as user friendly as possible. It is easily applied to many quantum optical or quantum information systems with more than one multi-level system. We first review the basics of the permutation symmetry for multi-level systems in quantum master equations. The application of PsiQuaSP to quantum dynamical problems is illustrated with several typical, simple examples of open quantum optical systems.

Optical and microwave control of germanium-vacancy center spins in diamond

A solid-state system combining a stable spin degree of freedom with an efficient optical interface is highly desirable as an element for integrated quantum optical and quantum information systems. We demonstrate a bright color center in diamond with excellent optical properties and controllable electronic spin states. Specifically, we carry out detailed optical spectroscopy of a Germanium Vacancy (GeV) color center demonstrating optical spectral stability. Using an external magnetic field to lift the electronic spin degeneracy, we explore the spin degree of freedom as a controllable qubit. Spin polarization is achieved using optical pumping, and a spin relaxation time in excess of 20 $\mu$s is demonstrated. Optically detected magnetic resonance (ODMR) is observed in the presence of a resonant microwave field. ODMR is used as a probe to measure the Autler-Townes effect in a microwave-optical double resonance experiment. Superposition spin states were prepared using coherent population trapping, and a pure dephasing time of about 19 ns was observed. Prospects for realizing coherent quantum registers based on optically controlled GeV centers are discussed.

Algorithms for Establishment and Reconfiguration of Optical Information Network for Multi-Agent Robotic System

Background/Objectives: Multi-agent Robotic Systems (MRS) with supervisory control can solve important practical tasks. For efficient MRS operation it is required to provide high speed (over 1 Gb/s) wireless communication between its agents. Methods: The implementation of the required high-speed data interchange in a multi-agent system is only possible when using wireless optical links. Low divergence of laser radiation is an important advantage of these lines, but it greatly complicates the task of establishing and reconfiguring optical information systems. Findings: The paper discusses possible algorithms for solving problems of the establishment and reconfiguration of an optical information system with respect to MRS, which is being developed within the framework of an applied research funded by the Ministry of Education and Science of the Russian Federation. Improvements/Novelty: By means of dynamic reconfiguration of the network the proposed algorithms for optical information network construction enable to provide reliable data transfer between the MRS agents at their mutual movement and link loss variation.

Features of Establishing Laser Communication Systems for Multi-Agent Robotic Systems

Background/Objectives: The article discusses the requirements for optical information systems intended for use in MRSs, the necessary software composition, as well as sound technical solutions, which can be used in the development of OISs. Methods: The conducted analysis of the scientific and patent literature enabled to highlight the most promising technical solutions which are integrated into the proposed concept for the system construction. Findings: MRS operation requires the system agents to process in real-time mode large amounts of information about the environment and a high speed (over 1 Gb/s) of the wireless exchange of information with a network-centric control point and between the MRS agents, and through a large number of channels simultaneously (up to several dozen). For these reasons, in advanced MRSs the open optical channel communication should be considered as the main means of communication. Improvements/ Novelty: The proposed concept for constructing a system is based on the synthesis of ‘all-optical’ circuit of open optical communication and scanning system that is typical for laser radar systems. Keywords: Communication Terminal, Laser Beacon, Multi-Agent Robotic System, Optical Amplifier, Optical Information System, Position-Sensitive Receiver, Reconfiguration of Communication Channels, Signal Laser Channel, Tracking Circuit

Toward the Physical-Information Fundamentals of Three-Dimensional Displays

The well-known groups of information three-dimensional displays (further—3D displays) with habitual names “stereoscopic,” “holographic,” “volumetric,” “integral imaging,” “light field,” etc., were historically formed without any common classification criteria. However, 3D displays as physical (optical) information systems should have the fundamental classification criteria. Such criteria are introduced in this paper in the form of physical-information modalities (further – modalities) identifying the physical-information formats of 3D image recordings in the working media of 3D displays. The modalities are based on four physical-information categories defined as four possible combinations of two kinds of 3D scene data representation (the object O representation and the representation by angular spectrum S of spherical waves) and two physical forms of each representation implementation (the ray optics R and diffraction optics D concepts). The modality of 3D display defines the primary physical-information properties of 3D image recording in the working medium. The true 3D image properties follow from the primary ones taking into account the relevant psychophysiological properties of the human visual system. The human visual system directly perceives 3D image light distribution that have passed through the optical scheme of 3D display after exiting the working medium. The limits of the proposed theory are discussed.

Design and Analysis of Disordered Optical Nanoantenna Structures

Nanoantennas are optical wave radiating structures operating based on the same physical principles as those underlying their radio-frequency counterparts. However, the physical properties of materials in the optical range of frequency cause different response to the incident electromagnetic field leading to novel applications in optics. The conventional methods for the analysis and design of antennas need to be modified for these structures. In this paper, an integral equation formulation using the complex images Green's function technique is employed to model the optical wave interactions with nanoantennas embedded in multilayer media. The developed method is combined with the simulated annealing algorithm to design and optimize structures composed of strongly coupled nanoscale scatterers. It is shown that not only can they lead to improved efficiency in optical devices, but also orthogonal transmission channels are attainable when they are excited properly. The latter provides a new scheme for encoding and multiplexing signals in optical information systems.

On personal-use displays for virtual environments with augmented reality

Head-mounted displays for common-use optical information systems of three types (retroreflective, immersive, and transparent) are considered. Advantages of transparent displays equipped by real object distance meters and occlusive masks for correct interposition and occlusion of virtual and real objects are demonstrated.

Road traffic information using a dedicated radio beacon

Traffic information is available on national and local FM radio throughout Europe. Dedicated motorway FM radio frequencies exist in some European countries. Radio traffic information limited coverage areas also exist in different countries. In this article, we present, develop and evaluate a radio beacon that instantly delivers traffic information to oncoming drivers over communication ranges several hundred meters in distance. This beacon uses a low power co-channel repeater to achieve a single isofrequency seamless communication network. The proposed local beacon effectively overrides the network-wide signal for a targeted road segment. The beacon is operated over large audience frequencies. The aim of this beacon is to deliver emergency information to drivers, using the existing unmodified car radios. No particular action is necessary for the car drivers to receive the alert information transparently. To enhance the beacon effectiveness, Radio Data System (RDS) and RDS Traffic Message Channel (RDS–TMC) services are also supported. This particular Vehicle to Vehicle communication system is intended to work as a complementary means to existing optical driver information systems. The FM radio beacon objectives are described and some initial on site measurements are performed to define the beacon technical requirements. The theoretical concept of the beacon is detailed and some associated laboratory measurements used to validate its working mode are provided. A technical description of a prototype equipment assembly is presented. Results obtained during experimentation campaigns along a motorway network are analyzed.

Increasing the efficiency of optical information systems by rational distribution of optical degrees of freedom

Optical systems transmit information of various types, including spatial (x, y, z components), temporal, spectral, polarization, and phase. In practice, it is often desired to evaluate the volume of information that is necessary for optimum use of an optical device. It is important to ensure that the system possesses the maximum number of degrees of freedom for certain types of information. This can be achieved through rational exchange of the optical information types that do not favor reaching a desired goal with the aid of a given device for useful types of information. An optimum model should take into account the hierarchy of the types of optical information and introduce weight functions based on the usefulness of each particular optical degree of freedom for solving the tasks of the given device.

Department of Optical Information Systems (OS) - Sensors and Instruments for Space- and Airborne Applications

Department of Optical Information Systems (OS) - Sensors and Instruments for Space- and Airborne Applications

Phase-dependent coherent population trapping and optical switching

We propose a scheme for achieving phase-dependent coherent population trapping, showing that both the dark state of the atoms and light propagation dynamics depend on the relative phase of the fields. The atomic coherence prepared via adiabatic process plays a key role in the interaction of light with matter. And an optical switching based on the phase-controlled quantum interference is implemented, which may have potential application in high-speed optical communications and quantum information systems.