Light Control Research Articles

Nanophotonics with Plasmonic Nanorod Metamaterials

AbstractTaking advantage of their unique and tuneable electromagnetic properties, plasmonic metamaterials constitute a versatile platform for a variety of applications ranging from high‐resolution imaging, sensing and spontaneous emission engineering to ultrafast nonlinear optics and light polarization control. Here, recent advances in the design and applications of plasmonic metamaterials based on aligned metallic nanorod assemblies are reviewed, and the fast‐developing trends in their exploitation in nanophotonics are outlined. The fabrication of the nanorod‐based metamaterials is introduced and their linear and nonlinear optical properties are presented from both microscopic and phenomenological considerations. Multiscale structuring allowing precise engineering of the electromagnetic modes supported by the nanorod metamaterials, as well as nonlocal spatial dispersion effects and their impact on nanophotonic performance are discussed. To illustrate the developing field of practical applications of these metamaterials, some of their main application domains in sensing, photochemistry and nonlinear optics are overviewed and novel designs of anisotropic metamaterials directly derived from the nanorod architecture are introduced.

OptoLacI: optogenetically engineered lactose operon repressor LacI responsive to light instead of IPTG.

Optogenetics' advancement has made light induction attractive for controlling biological processes due to its advantages of fine-tunability, reversibility, and low toxicity. The lactose operon induction system, commonly used in Escherichia coli, relies on the binding of lactose or isopropyl β-d-1-thiogalactopyranoside (IPTG) to the lactose repressor protein LacI, playing a pivotal role in controlling the lactose operon. Here, we harnessed the light-responsive light-oxygen-voltage 2 (LOV2) domain from Avena sativa phototropin 1 as a tool for light control and engineered LacI into two light-responsive variants, OptoLacIL and OptoLacID. These variants exhibit direct responsiveness to light and darkness, respectively, eliminating the need for IPTG. Building upon OptoLacI, we constructed two light-controlled E.coli gene expression systems, OptoE.coliLight system and OptoE.coliDark system. These systems enable bifunctional gene expression regulation in E.coli through light manipulation and show superior controllability compared to IPTG-induced systems. We applied the OptoE.coliDark system to protein production and metabolic flux control. Protein production levels are comparable to those induced by IPTG. Notably, the titers of dark-induced production of 1,3-propanediol (1,3-PDO) and ergothioneine exceeded 110% and 60% of those induced by IPTG, respectively. The development of OptoLacI will contribute to the advancement of the field of optogenetic protein engineering, holding substantial potential applications across various fields.

Thermo‐Optical Bistability Enabled by Bound States in The Continuum in Silicon Metasurfaces

AbstractThe control of light through all‐optical means is a fundamental challenge in nanophotonics and a key effect in optical switching and logic. The optical bistability effect enables this control and can be observed in various planar photonic systems such as microdisk and photonic crystal cavities and waveguides. However, the recent advancements in flat optics with wavelength‐thin optical elements require nonlinear elements based on metastructures and metasurfaces. The performance of these systems can be enhanced with high‐Q bound states in the continuum (BIC), which leads to intense harmonic generation, improved light‐matter coupling, and pushes forward sensing limits. This study reports enhanced thermo‐optical nonlinearity and the observation of optical bistability in an all‐dielectric metasurface membrane with BIC. Unlike many other nanophotonic platforms, metasurfaces allow for fine control of the quality factor of the BIC resonance by managing the radiative losses. This provides an opportunity to control the parameters of the observed hysteresis loop and even switch from bistability to optical discrimination by varying the angle of incidence. Additionally, this work proposes a mechanism of nonlinear critical coupling that establishes the conditions for maximal hysteresis width and minimal switching power, which has not been reported before. The study suggests that all‐dielectric metasurfaces supporting BICs can serve as a flat‐optics platform for optical switching and modulation based on strong thermo‐optical nonlinearity.

Photovoltaic parameters improvement via size control of monodisperse Mie-resonant nanoparticles in perovskite solar cells

Optically resonant Mie-resonant nanoparticles are powerful tools for light control at the nanoscale, which have been employed for such applications as coloration, and metaoptics, where the size and shape of nanoparticle play a critical role in the device performance. Moreover, such nanoparticles are successfully used for the improvement of perovskite solar cells. However, there is a lack of experimental knowledge on how the size of Mie-resonant nanoparticles affects the improvement of parameters in the photovoltaic devices. Here we apply monodisperse silicon nanoparticles to investigate optical effects responsible for the improvement of perovskite solar cells. The experimental analysis shows that the most optimal sizes of silicon nanoparticles for the perovskite with bandgap 1.53 eV are in the range 140–160 nm. The main reason for such improvement is the optimization of absorption in the perovskite layer around wavelength 500–800 nm, where the Mie resonances in nanoparticles are not completely damped but contribute to additional light trapping and scattering. Our results can be useful not only for further optimization of perovskite solar cells, but also pave the way for improvement of a broader range of photovoltaic devices with integrated Mie-resonant nanoparticles.

65‐5: Light Control Polarizer for Automotive as an Alternative to Light Control Films

We have developed a new polarizer system named “Light Control Polarizer (LCP)” that has a shading effect comparable to that of light control films (LCF) while significantly improving on‐axis luminance loss. The LCP exhibits a louver effect of 1.4% at a 60° polar angle and 1.1% at a ‐60° polar angle in vertical direction, with a 20% increase in on‐axis luminance over LCF and a 12% increase in contrast ratio (CR). These characteristics allow the LCP to work as an alternative to LCF providing with effective light shielding in the vertical direction without sacrificing display luminance.

Evaluation on LED lighting driving power supply for urban rail vehicles based on adaptive PID algorithm

LED (Light Emitting Diode) lighting has the characteristics of efficiency, environmental protection, energy conservation, and so on. It is more and more widely used in the lighting system of urban rail vehicles. The research on the LED lighting system of rail vehicles has important practical significance. As the core of the LED lighting system of rail vehicles, the LED control system of urban rail vehicles is the key to ensure the stable operation of the entire LED lighting system. The lighting environment of urban rail vehicles needs LED lighting system with good power stability, long life of drive chip, high feedback accuracy, fast processing speed, intelligent algorithm efficiency and other characteristics to ensure continuous operation, and also should have strong anti-interference ability and excellent static performance. However, conventional lighting systems not only have low life, but also have poor stability. Therefore, this paper studied the uniqueness and functional module analysis of LED driving power supply by analyzing the causes and disadvantages of LED lighting, and finally optimized the design of LED lighting control system by using the adaptive PID (Proportional Integral Differential) algorithm. Through comparison, the brightness acquisition quality of LED lighting control system was 21.2 % higher than that of traditional lighting control system, and the lighting control effect was 18 % higher than that of traditional lighting control system. In short, the selection of LED lighting driving power affects the lighting effect of rail vehicles.

Advanced Traffic Light Controller using FPGA and ARDUINO

This study presents a novel approach to develop a traffic light controller using FPGA and Arduino platforms. The objective is to design a robust, adaptable, and efficient traffic management system. Methodology involves hardware integration of FPGA for real-time processing and Arduino for interfacing with sensors and actuators. The proposed system utilizes FPGA's parallel processing capabilities for rapid decision-making and Arduino's flexibility for sensor data acquisition and actuator control. Performance evaluation includes simulation and real-world testing to assess reliability, response time, and scalability. Results demonstrate the effectiveness of the proposed controller in optimizing traffic flow and improving intersection safety.

Intelligent Light Emitting Diode Flashing Supplementary Lighting Control Design and Its Big Data Illumination Analysis

Considering the inherent advantages of the Light Emitting Diode (LED) in the field of illumination, this work designs an intelligent supplementary lighting system using LED as the light source. Combining microcontroller and electronic circuit theory, the circuit is built with the microcontroller PIC16F873 as the core control chip. The system utilizes an external 220 V AC-20 V DC conversion power supply, hence operating on a 20 V DC power source. The system consists of four hardware parts: the onboard power supply uses TI-produced TPS54331 as the control chip to achieve voltage conversion; the external signals (flashing and burst flashing signals) are isolated from the microcontroller through an optocoupler circuit; the PWM pulses output from the microcontroller’s RC1/CCP2 pins drive the corresponding switching tubes to achieve the flashing function; the flashing synchronization signal is output externally after optocoupler isolation, and its synchronous output with the flashing signal is achieved through an optocoupler after LED conduction; the circuit is established using TI-produced differential bus transceiver SN65LBC184D to convert the external 485 differential signal to the level signal required by the microcontroller. In the experiment, after completing the hardware design, connecting the LED panel, and debugging the test program, it is found that the designed lighting system has a good supplementary lighting effect. According to the PWM output waveform, the flashing effect meets the design expectations. The Hadoop big data computing platform is introduced. Simulation testing reveals that under no backlight conditions, the system achieves an illumination intensity of around 20 klx at a distance of about 10 meters. With backlight conditions, the system maintains an illumination intensity of around 1.5 klx at a distance of about 10 meters. Further calculations are performed to analyze the variation in foot traffic within the test area’s illumination over 24 hours. The total illumination intensity during different time intervals is compiled, confirming that the system can autonomously adjust the illumination intensity of the area based on changes in foot traffic.

Traffic Monitoring and Signal Controlling using RFID for Emegency Vehicles

Abstract: This paper presents the concept, Traffic Monitroting and signal controlling using RFID technology to prioritize ambulance passage during emergencies. Traffic lights are crucial for managing the flow of vehicles on the road. In particular, when there are emergencies, the traffic situation is getting worse. Emergency vehicles find it challenging to cross busy road during periods of traffic congestion. A medical emergency vehicles like ambulances, or victims of accidents must be transferred to it as soon as possible. They could be late for rescue efforts because of traffic signals. Identification of emergency vehicles, control of traffic lights, and provision of a clear path for their travel are the objectives of our paper. The main element of this system that implements the control system is radio frequency Identification (RFID). Through RFID detection, the system identifies the presence of an ambulance approaching any lane and promptly initiates a sequence wherein traffic lights for the ambulance's intended lane turn green, while simultaneously halting traffic flow in other lanes. By integrating RFID technology into the traffic management infrastructure, the prototype ensures swift and efficient response to emergency situations, minimizing delays in medical assistance. The system's intelligent algorithm enables it to override regular traffic light patterns, granting immediate passage to ambulances without compromising safety or causing disruptions to traffic flow in adjacent lanes. This approach enhances emergency response capabilities, optimizing the delivery of critical healthcare services and potentially saving lives in urgent medical situations. The system's ability to dynamically adapt traffic signals based on real time ambulance detection underscores its potential to revolutionize emergency response protocols, contributing to enhanced public safety and well-being in densely populated urban areas. The RFID tag helps to verify that emergency vehicles The emergency vehicle can clear all junctions without wasting time at the traffic signals this keeps happening until the ambulance arrives at its destination.

Implementation of Sensor based Energy Conservation System for College Library

Abstract: The lighting libraries and maintaining fans and lights need an extensive amount of energy in the majority of educational establishments. Nevertheless, this may lead to more expenses and wasteful energy use. We have created an improved lighting control system to solve this problem and reduce energy consumption during daylight and vacant hours. This system makes sure that the library's light connections and fans stay off while no students are present and turn on automatically when they do. For the purpose of managing the automated lighting system, we created an integrated module. The contrast of the library is determined as well with an LDR sensor

Microcontroller Based Automatic Street Light Control by Using LDR & IR Sensors

This project aims at designing and executing the advanced development in embedded systems for energy saving of street lights. Nowadays, human has become too busy, and is unable to find time even to switch the lights wherever not necessary. The present system is like, the street lights which will be switched on in the evening before the sun sets and they are switched off the next day morning after there is sufficient light on the roads. This paper gives the best solution for electrical power wastage. Also the manual operation of the lighting system is completely eliminated. In this the two sensors are used which are Light Dependent Resistor(LDR) sensor to indicate a day/night time and theIRsensors to detect the movement on the street. The microcontroller PIC16F877A is used as brain to control the street light system, where the programming language used for developing the software to the microcontroller is C-language. Finally, the system has been successfully designed and implemented as prototype system. Key Words: Embeded systems, Microcontroller, LDR ,IR, Lighting

Local Light Field Control Enables Efficient Quantum Dot Color Conversion Films for Mini‐LED Backlit Displays

AbstractQuantum dot (QD) color conversion films (QD‐CCFs) are used in ultrahigh definition (UHD) Mini‐LED backlit displays due to their narrow band emission and high color purity. However, their poor light conversion efficiency (LCE) leads to greater film thickness and thus high cost. Herein, this study proposes a local light field control strategy to enhance the LCE of QD‐CCFs using high‐refractive BN nanosheets. The LCEs of the green and red QD‐CCFs can increase from 29.9% and 34.8% to 67.4% and 91.0% after adding BN nanosheets, respectively. Combining the experimental data with the finite‐difference time domain (FDTD) simulations, the enhanced LCEs can be attributed to observably increased blue light absorption and improved light extraction efficiency of the light emitted from QDs. The white Mini‐LEDs, prepared by integrating the optimized QD‐CCFs containing BN nanosheets with blue Mini‐LED chips, show a high luminous efficiency of 70.2 lm W−1, a high external quantum efficiency of 36.2%, and a wide color gamut of 96.3% Rec. 2020 standards. This work provides an interesting idea for designing high‐efficiency QD‐CCFs toward low‐cost UHD Mini‐LED backlit displays.

A verified low-level implementation and visualization of the adaptive exterior light and speed control system

In this article, we present an approach to the ABZ 2020 case study that differs from those usually presented at ABZ: Rather than using a (correct-by-construction) approach following a formal method, we use C for a low-level implementation instead. We strictly adhere to test-driven development for validation, and only afterwards apply model checking using CBMC for verification. While the approach has several benefits compared to the more rigorous approaches, it also provides less mathematical clarity and overall less thorough verification. In consequence, our realization of the ABZ case study serves as a baseline reference for comparison, allowing to assess the benefit provided by the various formal modeling languages, methods and tools.

Optimal growth conditions to enhance Chlorella vulgaris biomass production in indoor phyto tank and quality assessment of feed and culture stock

Commercial microalgae cultivation is a dynamic field with ongoing efforts to improve efficiency, reduce costs, and explore new applications. We conducted a study to examine how different light exposure periods affect Chlorella vulgaris's growth. We employed a Phyto tank batch system of approximately 3.5 L with LED light control, controlled airflow, and sterilized bags, maintained at 22.0 ± 2.0 °C indoors. Various methods, including spectrophotometry, and cell counter were employed to monitor Chlorella vulgaris growth under different light exposure cycles. Additionally, quality analysis as feed source was employed by proximate, amino acid, beta-glucan, and microbial content analysis. The results revealed significant variations in C. vulgaris biomass production based on light exposure duration. Notably, the 16:8-h light-dark photoperiod exhibited the highest biomass concentration, reaching 6.48 × 107 ± 0.50 cells/mL with an optical density (OD) of 1.165 absorbance at 682 nm. The 12:12-h light-dark photoperiod produced the second-highest biomass concentration, with 2.305 × 106 ± 0.60 cells/mL at an OD of 0.489. Proximate analysis of dry algae powder revealed low lipid content (0.48 %), high protein content (37.61 %), variable ash concentration (average 10.75 %), and a significant carbohydrate fraction (51.16 %) during extended daylight and shorter dark periods. Amino acid analysis identified nine essential amino acids, with glutamic acid being the most abundant (17.7 %) and methionine the least (0.4 %). Furthermore, quality analysis and microbiological assays demonstrated that the C. vulgaris biomass is well-suited for fish and livestock use as a feed source and possibility as human nutraceuticals. These findings can be considered more environmentally friendly and ethically sound due to the absence of genetic modification.

Application Strategies of Automatic Addressable Single-Lamp Control Technology in Tunnel Lighting

The article mainly studies the application strategy of automatic addressable single-lamp control technology in tunnel lighting. It encompasses an introduction to this technology, an analysis of the tunnel lighting system using automatic addressable single-lamp control technology, and outlines the main development direction for this technology in modern tunnel lighting. The aim is to offer insights that can inform the rational deployment of this technology, thereby enhancing the lighting control effectiveness in modern tunnels and meeting their specific lighting requirements more effectively.

Flexible terahertz phase shifter for optically controlled polydimethylsiloxane-vanadium dioxide composite film

In the terahertz (THz) band, modulation research has become a focal point, with precise control of the phase shift of THz waves playing a pivotal role. In this study, we investigate the optical control of THz phase shift modulation in a polydimethylsiloxane (PDMS)-vanadium dioxide (VO2) flexible material using THz time-domain spectroscopy. Under the influence of an 808-nm continuous wave (CW) laser with power densities ranging from 0 to 2.74 W/cm2, the PDMS-VO2 flexible material exhibits significant phase shift modulation in the frequency range of 0.2 to 1.0 THz. The maximum optical-pumping phase shift reaches 0.27π rad at 1.0 THz in a composite material with a VO2 mass fraction of 5% and a thickness of 360 µm, and the amplitude transmittance from 0.2 THz to 1.0 THz exceeds 70%. Furthermore, the composite material exhibits good stability under at least 640 switching cycle times, as confirmed through repeatability tests. The proposed composite devices offer a new approach for more flexible phase shift modulation owing to the flexibility of the composite material and the non-contact and precise modulation of light control. Additionally, the stress-adjustable characteristics of flexible materials make them highly suitable for use in wearable THz modulators, highlighting their significant application potential.

Broadband wavelength designable achromatic grating based on a cholesteric liquid crystal template

Liquid crystal (LC) gratings have played important roles in light field control due to the advantages of being lightweight, low cost, having no moving parts, and low power consumption. However, the chromatic aberration limits the bandwidth of the LC device and affects the efficiency of the grating. To solve the chromatic aberration issue, a broadband wavelength designable achromatic grating is proposed. Different grating structures are integrated into a single-layer templated cholesteric liquid crystal (CLC) device, and the achromatic diffraction wavelength of the grating can be freely designed from the visible spectral region to the infrared range within the Bragg reflection band of the CLCs. The diffraction intensity of different orders can be changed with the electric field applied to meet the need for dynamic modulation. This grating shows suitable potential applications in optical communication and displays.

Light control ofthree-dimensional chromatin organization in soybean.

Higher-order chromatin structure is critical for regulation of gene expression. In plants, light profoundly affects the morphogenesis of emerging seedlings as well as global gene expression to ensure optimal adaptation to environmental conditions. However, the changes and functional significance of chromatin organization in response to light during seedling development are not well documented. We constructed Hi-C contact maps for the cotyledon, apical hook and hypocotyl of soybean subjected to dark and light conditions. The resulting high-resolution Hi-C contact maps identified chromosome territories, A/B compartments, A/B sub-compartments, TADs (Topologically Associated Domains) and chromatin loops in each organ. We observed increased chromatin compaction under light and we found that domains that switched from B sub-compartments in darkness to A sub-compartments under light contained genes that were activated during photomorphogenesis. At the local scale, we identified a group of TADs constructed by gene clusters consisting of different numbers of Small Auxin-Upregulated RNAs (SAURs), which exhibited strict co-expression in the hook and hypocotyl in response to light stimulation. In the hypocotyl, RNA polymerase II (RNAPII) regulated the transcription of a SAURs cluster under light via TAD condensation. Our results suggest that the 3D genome is involved in the regulation of light-related gene expression in a tissue-specific manner.

Photon-Dipole-Spin Interactions in M(TCNE)x/P(VDF-TrFE) Multiferroic Heterostructure Available for Bimodal Control of Multistate Data-Storage.

Organic multiferroic heterostructure is one of the most promising structures for the future design of high-density flexible energy-efficient data storage. Here, organic ferromagnetic metal(tetracyanoethylene) (M(TCNE))x/ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) multiferroic heterostructures are fabricated, where the excited state in M(TCNE)x interacted with localized dipole in P(VDF-TrFE) provides a key link for the interfacial coupling. Thus, aligned dipoles in P(VDF-TrFE) by external electric field can affect the magnetization of Fe(TCNE)x effectively to result in a pronounced magnetization-voltage (M-V) hysteresis loop. Moreover, light-induced electron-hole pairs in Fe(TCNE)x with long lifetime effectively interact with the dipoles in P(VDF-TrFE) to lead to an effect in external light control of electric polarization of P(VDF-TrFE). Overall, the organic multiferroic heterostructure provides the possibility of realizing two storage modes, light control of dipole as well as electric field control of spin, which can broaden multifunctional applications of organic multiferroic materials in the area of multistate storage.

Multi-Source Collaborative Control Technology of Photovoltaic Power Generation Based on Differential Evolution-Gray Wolf Optimization Algorithm

The existing photovoltaic power generation multi-source collaborative control technology cannot improve the control effect of microgrid, resulting in high peak load balancing cost of microgrid. Therefore, the photovoltaic power generation multi-source collaborative control technology based on differential evolution (DE)-gray wolf optimization (GWO) algorithm is adopted. The main components of the microgrid system, such as photovoltaic power generation equipment, hydroelectric power generation equipment, and battery pack, are modeled. With the goal of minimum peak cost and maximum transmission power, collaborative control of water, light and energy storage is carried out. The gray Wolf algorithm is used to solve the multi-objective problem of water and light storage in microgrid, and the gray Wolf algorithm is optimized by DE algorithm. Experiments show that the convergence speed of the optimized DEVOLU-Gray Wolf algorithm is obviously accelerated, and the problem of falling into the local optimal solution is completely avoided. After the application of this method, the photovoltaic, hydraulic, and battery of the microgrid run in order, ensure the smooth operation of the microgrid, and improve the economic benefit of the microgrid.