Reversible optical control of the metal-insulator transition across the epitaxial heterointerface of a VO_(2)/Nb:TiO_(2) junction

Optical control of exotic properties in strongly correlated electron materials is very attractive owing to their potential applications in optical and electronic devices.Herein,we demonstrate a vertical heterojunction made of a correlated electron oxide thin film VO_(2) and a conductive 0.05 wt% Nb-doped TiO_(2) single crystal,whose metal-insulator transition(MIT)across the nanoscale heterointerface can be efficiently modulated by visible light irradiation.The magnitude of the MIT decreases from ~350 in the dark state to ~7 in the illuminated state,obeying a power law with respect to the light power density.The junction resistance is switched in a reversible and synchronous manner by turning light on and off.The optical tunability of it is also exponentially proportional to the light power density,and a 320-fold on/off ratio is achieved with an irradiance of 65.6 mW cm^(-2) below the MIT temperature.While the VO_(2) thin film is metallic above the MIT temperature,the optical tunability is remarkably weakened,with a one-fold change remaining under light illumination.These results are co-attributed to a net reduction(~15 meV)in the apparent barrier height and the photocarrier-injection-induced metallization of the VO_(2) heterointerface through a photovoltaic effect,which is induced by deep defect level transition upon the visible light irradiance at low temperature.Additionally,the optical tunability is minimal,resulting from the quite weak modulation of the already metallic band structure in the Schottky-type junction above the MIT temperature.This work enables a remotely optical scheme to manipulate the MIT,implying potential uncooled photodetection and photoswitch applications.

Genetic Encoding of a Photocaged Glutamate for Optical Control of Protein Functions

Genetic encoding of photocaged noncanonical amino acids provides a powerful tool to study protein functions through optical control but is not yet available for acidic amino acids.Herein,we report the first site-specific genetic encoding of a photocaged glutamate,4-methoxy-7-nitroindolinyl caged glutamate(MNI-Glu),into recombinant proteins via an expanded genetic code through evolved EcLeuRS/tRNA pair.Using two enzymes as examples,we demonstrate that substituting the conserved-active-site glutamate of a secreted alkaline phosphatase and a protease HRV3C to MNI-Glu allows photoregulatory control of their enzymatic activities.Our approach is an important addition to the photocaged noncanonical amino-acid toolbox and provides a general method to photocontrol protein activity based on caging a critical glutamate.

A Novel Stateful PCE-Cloud Based Control Architecture of Optical Networks for Cloud Services

The next-generation optical network is a service oriented network,which could be delivered by utilizing the generalized multiprotocol label switching(GMPLS) based control plane to realize lots of intelligent features such as rapid provisioning,automated protection and restoration(P&R),efficient resource allocation,and support for different quality of service(QoS) requirements.In this paper,we propose a novel stateful PCE-cloud(SPC)based architecture of GMPLS optical networks for cloud services.The cloud computing technologies(e.g.virtualization and parallel computing) are applied to the construction of SPC for improving the reliability and maximizing resource utilization.The functions of SPC and GMPLS based control plane are expanded according to the features of cloud services for different QoS requirements.The architecture and detailed description of the components of SPC are provided.Different potential cooperation relationships between public stateful PCE cloud(PSPC) and region stateful PCE cloud(RSPC) are investigated.Moreover,we present the policy-enabled and constraint-based routing scheme base on the cooperation of PSPC and RSPC.Simulation results for verifying the performance of routing and control plane reliability are analyzed.

Phase Control of Transient Optical Properties of Double Coupled Quantum-Dot Nanostructure via Gaussian Laser Beams

We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorption and dispersion of the probe field can be dramatically influenced by the relative phase between applied fields and intensity of the Gaussian laser beams.Transient and steady-state behaviors of the probe field absorption and dispersion are discussed to estimate the required switching time.The estimated range is between 5-8 ps for subluminal to superluminal light propagation.

Optical phase front control in a metallic grating with equally spaced alternately tapered slits

A technique capable of focusing and bending electromagnetic （EM） waves through plasmonic gratings with equally spaced alternately tapered slits has been introduced. Phase resonances are observed in the optical response of transmission gratings, and the EM wave passes through the tuning slits in the form of surface plasmon polaritons （SPPs） and obtains the required phase retardation to focus at the focal plane. The bending effect is achieved by constructing an asymmetric phase front which results from the tapered slits and gradient refractive index （GRIN） distribution of the dielectric material. Rigorous electromagnetic analysis by using the two-dimensional （2D） finite difference time domain （FDTD） method is employed to verify our proposed designs. When the EM waves are incident at an angle on the optical axis, the beam splitting effect can also be achieved. These index-modulated slits are demonstrated to have unique advantages in beam manipulation compared with the width-modulated ones. In combination with previous studies, it is expected that our results could lead to the realization of ootimum designs for plasmonic nanolenses.

Determination of Impurity Silicon in Anticancer Drug (Ge-132) by Electrothermally Atomised Atomic Absorption Spectrometry with Optical Temperature Control Accessory

The present paper describes the ashing and atomization processes in silicon analysis by electrothermally atomised atomic absorption spectrometry(EAAAS) with an uncoat-ed graphite tube, a pyrolytically coated graphite tube and a tungsten-coated graphitetube. The sensitivity and linear range of three graphite tubes were compared. By using optical temperature control accessory, the signals are enhanced by a factor of 2 and the germanium interferences in the determination of silicon are eliminated. The effects of time constant and carrier gas flow-rate on the determination of silicon were also tested. The sample can be directly analyzed in its aqueous solution without any pretreatment. The measurements of samples containing 0. 2 μg/mL and 0. 4 μg/mL silicon were run ten times and the variation coefficient is 4. 9% and 2.6%, respectively. The recovery tests for carboxyethyl germanium sesquioxide(Ge-132) synthesized and imported were performed, and the recoveries are 97. 0% and 110%, respectively. Keywords Carboxyethyl germanium sesquioxide, Electrothermally atomised atomic absorption spectrometry, Silicon

CONTROL SYSTEM OF MAGNETIC BEARINGS BASED ON LINEAR QUADRATIC METHOD OF OPTIMAL CONTROL STRATEGY

A state equation for radical 4-degree-of-freedom active magnetic bearings isbuilt, and the approach on how to use linear quadratic method of optical control theory to design acentralized and decentralized parameters control system is introduced, and also Matlab language isused to simulate and analyze. The simulation results have proved that the differences are smallbetween centralized parameters and decentralized parameters control system. The conclusions ofexperiments have shown that decentralized controllers designed from optimal state feedback theorymeet the requirements of active magnetic bearing system. The vibration amplitude of the rotor isabout 20 mu m when the speed of the rotor runs between 0 to 60 000 r/min. This method may be used inthe study and design of controllers of magnetic bearings.

Advances in optical engineering for future telescopes

Significant optical engineering advances at the University of Arizona are being made for design, fabrication, and construction of next generation astronomical telescopes. This summary review paper focuses on the technological advances in three key areas. First is the optical fabrication technique used for constructing next-generation telescope mirrors. Advances in ground-based telescope control and instrumentation comprise the second area of development. This includes active alignment of the laser truss-based Large Binocular Telescope(LBT) prime focus camera, the new MOBIUS modular cross-dispersion spectroscopy unit used at the prime focal plane of the LBT, and topological pupil segment optimization. Lastly, future space telescope concepts and enabling technologies are discussed. Among these, the Nautilus space observatory requires challenging alignment of segmented multi-order diffractive elements. The OASIS terahertz space telescope presents unique challenges for characterizing the inflatable primary mirror, and the Hyperion space telescope pushes the limits of high spectral resolution, far-UV spectroscopy. The Coronagraphic Debris and Exoplanet Exploring Pioneer(CDEEP) is a Small Satellite(Small Sat) mission concept for high-contrast imaging of circumstellar disks and exoplanets using vector vortex coronagraph. These advances in optical engineering technologies will help mankind to probe, explore, and understand the scientific beauty of our universe.

Redox Controllable Switch of Crystalline Phase and Physical Property in SrVO_x Epitaxial Films

Transition-metal oxides have attracted much attention due to its abundant crystalline phases and intriguing physical properties. However, some of these compounds are difficult to be fabricated directly in film form due to the ease of valence variation of transition-metal elements.In this work, we reveal the reversible structural transition between SrVO3 and Sr2V2O7 films via thermal treatment in oxygen atmosphere or in vacuum. Based on this, Sr2V2O7 epitaxial films are successfully synthesized and studied. Property characterizations show that the semitransparent and metallic SrVO3 could reversibly switch into transparent and insulating Sr2V2O7, implying potential applications in controllable electronic and optical devices.

Anticontrol of Quantum Chaos in Hamiltonian Systems

We present a method of realizing anticontrol chaos in a quantum confined system consisting of N two-levelatoms within a cavity, using a time-delayed optic field. The delay time plays a construction and organization role forproducing temporal chaos, while the interaction between atoms and photons creates spatial chaos. The chaos is quitesensitive to small time delayed. The spectral decomposition of the Hamiltonian obtained by using projection methodologyreveals that evolution of the left eigenvectors shows quite complicated chaotic fashions. The method we proposed maybe easily tested in experiment, and provides a general method using a sort of driving optic field to achieve anticontrol ofchaos for quantum systems.

An Arrangement of Channels and Transceivers in Optical Packet Switching Networks

Based on a media access and control（MAC）protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing（DWDM）networks is proposed in this paper.In order to reduce the cost of nodes,fixed transmitters and receivers are used instead of tunable transmitters and receivers.Two fixed transmitters and many fixed receivers are used in each node in the scheme.The average waiting delay of this scheme is analyzed through mathematics and computer simulation.The result shows that the property of the scheme is almost the same as using tunable transmitter and receiver.Furthermore,if the tuning time of tunable transmitters is taken into account,the performance of the tunable transmitter scheme is poor than this scheme at the average waiting delay and throughput of the network.

Decoupling Algorithms for the Gravitational Wave Spacecraft

The gravitational wave spacecraft is a complex multi-input multi-output dynamic system.The gravitational wave detection mission requires the spacecraft to achieve single spacecraft with two laser links and high-precision control.Establishing one spacecraftwith two laser links,compared to one spacecraft with a single laser link,requires an upgraded decoupling algorithmfor the link establishment.The decoupling algorithmwe designed reassigns the degrees of freedomand forces in the control loop to ensure sufficient degrees of freedomfor optical axis control.In addressing the distinct dynamic characteristics of different degrees of freedom,a transfer function compensation method is used in the decoupling process to further minimize motion coupling.The open-loop frequency response of the systemis obtained through simulation.The upgraded decoupling algorithms effectively reduce the open-loop frequency response by 30 dB.The transfer function compensation method efficiently suppresses the coupling of low-frequency noise.

Controlling antifungal activity with light:Optical regulation of fungal ergosterol biosynthetic pathway with photo-responsive CYP51 inhibitors

Invasive fungal infections(IFIs)have been associated with high mortality,highlighting the urgent need for developing novel antifungal strategies.Herein the first light-responsive antifungal agents were designed by optical control of fungal ergosterol biosynthesis pathway with photocaged triazole lanosterol 14a-demethylase(CYP51)inhibitors.The photocaged triazoles completely shielded the CYP51inhibition.The content of ergosterol in fungi before photoactivation and after photoactivation was 4.4%and 83.7%,respectively.Importantly,the shielded antifungal activity(MIC80≥64μg/m L)could be efficiently recovered(MIC80=0.5—8μg/m L)by light irradiation.The new chemical tools enable optical control of fungal growth arrest,morphological conversion and biofilm formation.The ability for highprecision antifungal treatment was validated by in vivo models.The light-activated compound A1 was comparable to fluconazole in prolonging survival in Galleria mellonella larvae with a median survival of 14 days and reducing fungal burden in the mouse skin infection model.Overall,this study paves the way for precise regulation of antifungal therapy with improved efficacy and safety.

Histological and Physiological Investigation of Channelrhodopsin-2 and Halorhodopsin in the Dorsal Cochlear Nucleus

We have delivered viral vectors containing either Chop2 fused with GFP, Channelrhodopsin-2 （ChR2）, or Halorhodopsin （HaloR） fused with mCherry （to form light gated cation channels or chloride pumps, respectively）, into the dorsal cochlear nucleus （DCN）. One to eighteen months later we examined the CN and inferior colliculus （IC） for evidence of virally transfected cells and processes. Production of ChR2 and HaloR was observed throughout the DCN. Rhodopsin localization within neurons was determined, with elongate, fusiform and giant cells identified based on morphology and location within the DCN. Production of ChR2 and HaloR was found at both the injection site as well as in regions projecting to and from the DCN. Light driven neuronal activity in the DCN was dependent upon the wavelength and intensity of the light, with only the appropriate wavelength resulting in activation and higher intensity light resulting in more neuronal activity. Transfecting cells via viral delivery of rhodopsins can be useful as a tract tracer and as a neuronal marker to delineate pathways. In the future rhodopsin delivery and activation may be developed as an alternative to electrical stimulation of neurons.

Application of photopharmacology in agrochemicals

Photopharmacology is a novel technology in drug design that aims at solving poor drug selectivity.This technology is currently in the proof-of-concept phase and relies on the photoactivation or inactivation of photochromic ligands(PCLs)to regulate biological functions and living organisms.As potential molecular tools in future agriculture 4.0,the photochromic pesticides are effective in optical control of receptors,ion channels,living behaviors,and enzymes,which displays an innovative way of pesticide discovery.In this review,we highlight the progresses of the photoisomerized insecticides and fungicides.By integrating photoswitches,such as azobenzenes and diarylethenes,into pesticide molecules,several PCLs were developed for optical regulation of important insect or fungi targets in vivo,including GABARs,RyRs,nAChRs,SURs,sodium channels,GluCls,and SDH.The results are highly significant in revealing interactions of agrochemicals with their targets,biological functions,and living behaviors,and provide powerful toolkits in understanding ligand-receptor interactions.Moreover,there is a growing demand for a diverse range of PCLs,particularly those that are sensitive to red and NIR light or sunlight,for actual field use in agriculture.We envision that this particular mode of pesticide discovery is of great promise for overcoming the challenges posed by the improper use of agrochemicals.

Switching On/Off of Guide RNA by Photoinduced Strand Displacement for Functional Control of CRISPR/Cas9

Functional control of CRISPR/Cas9 is essential for precise gene manipulation.Chemical engineering of guide RNA(gRNA)provides diverse approaches for conditional control of CRISPR/Cas9 function with a variety of chemical reactive groups.However,previous investigations into chemically engineering gRNA only unidirectionally regulated the CRISPR/Cas9 function via stimuli-induced caging/decaging processes.Herein,we propose a combinatory strategy to engineer the dynamics of gRNA in which photocontrolled strand-displacement reactions coupled with sequence designs of gRNA can achieve lightinduced switching-on/off control of CRISPR/Cas9 function.Biochemical analysis and cellular gene regulation indicate this approach is capable of both activating and deactivating CRISPR/Cas9 activities using light irradiation.Moreover,photocontrolled multiplex modulations of gene expression for opposite regulatory effects have also been achieved simultaneously under the same cellular context.This work establishes an essential principle for construction of stimuli-induced switching-on/off modulations of gRNA that can greatly enrich the versatility of conditional control for a variety of CRISPR/Cas9-based applications.

An optically controlled SiC lateral power transistor based on SiC/SiCGe superjunction structure

An optically controlled SiC/SiCGe lateral power transistor based on superjunction structure has been proposed, in which n-SiCGe/p-SiC superjunction structure is employed to improve device figure of merit. Performance of the novel optically controlled power transistor was simulated using Silvaco Atlas tools, which has shown that the device has a very good response to the visible light and the near infrared light. The optoelectronic responsivities of the device at 0.5 μm and 0.7 μm are 330 mA/W and 76.2 mA/W at 2 V based voltage, respectively.

High-performance optical noncontact controlling system based on broadband PtTex/Si heterojunction photodetectors for human-machine interaction

Noncontact interaction systems have attracted considerable research attention in recent years because of convenient operation,sterility,and injury prevention.However,the insufficient sensing distance and weak robustness of noncontact interaction systems for complex environments limit their practical applications.Here,we designed an integrated optical noncontact controlling system(ONCS)based on PtTe_(x)/Si optoelectronic heterojunction array.Broadband sensitive photoresponse is realized at zero bias voltage,with excellent detectivity and responsivity,boosting the noncontact sensing distance to at least 150 mm.Consequently,the system can perform noncontact detection,encoding,and control by recognizing shadow-induced spatiotemporal sequence changes in heterojunction array photocurrents.As a proof of concept,different interactive functions have been demonstrated with good accuracy and robustness by encoding finger movement above the ONCS.This study provides a new perspective for constructing high-performance noncontact interaction systems.

GMPLS: IP-Centric Control Protocols for Optical Networks(Tutorial)

Recent advances in optical networking technologies, particularly DWDM and MEMS, promise the transmission and switching of huge bandwidth capacity. The carriers have convinced of that their revenue must be earned from efficient bandwidth management instead of unsophisticated increase in capacity. The distributed control plane can offer more flexibility, reliability and scalability, whose functions include addressing, resource and topology discovery, route computation, provisioning and restoration. Genera...

Creation of radially polarized optical fields with multiple controllable parameters using a vectorial optical field generator

A vectorial optical field generator(VOF-Gen) based on two reflective phase-only liquid crystal spatial light modulators enables the creation of an arbitrary optical complex field. In this work, the capabilities of the VOF-Gen in terms of manipulating the spatial distributions of phase, amplitude, and polarization are experimentally demonstrated by generating a radially polarized optical field consisted of five annular rings, the focusing properties of which are also numerically studied with vectorial diffraction theory. By carefully adjusting the relative amplitude and phase between the adjacent rings, an optical needle field with purely longitudinal polarization can be produced in the focal region of a high numerical aperture lens. The versatile method presented in this work can be easily extended to the generation of a vectorial optical field with any desired complex distributions.