Optical Control Research Articles

Programmable photonic latch memory.

Significant advancements in integrated photonics have enabled high-speed and energy efficient systems for various applications, from data communications and high-performance computing to medical diagnosis, sensing, and ranging. However, data storage in these systems has been dominated by electronic memories that in addition to signal conversion between optical and electrical domains, necessitates conversion between analog to digital domains and electrical data movement between processor and memory that reduce the speed and energy efficiency. To date, scalable optical memory with optical control has remained an open problem. Here, we report an integrated photonic set-reset latch as a fundamental optical static memory unit based on universal optical logic gates. As a proof of concept, experimental implementation of the universal logic gates and realistic simulation of the latch are demonstrated on a programmable silicon photonic platform. Optical set, reset, and complementary outputs, scalability to a large number of memory units via the independent latch supply light, and compatibility with wavelength division multiplexing scheme and different photonic platforms enable more efficient and lower latency optical processing systems.

Optical Control of Microtubule Accumulation and Dispersion by Tau-Derived Peptide-Fused Photoresponsive Protein

Optical Control of Microtubule Accumulation and Dispersion by Tau-Derived Peptide-Fused Photoresponsive Protein

Tools for Intersectional Optical and Chemical Tagging on Cell Surfaces.

We present versatile tools for intersectional optical and chemical tagging of live cells. Photocaged tetrazines serve as "photo-click" adapters between recognition groups on the cell surface and diverse chemical payloads. We describe two new functionalized photocaged tetrazine structures which add a light-gating step to three common cell-targeting chemical methods: HaloTag/chloroalkane labeling, nonspecific primary amine labeling, and antibody labeling. We demonstrate light-gated versions of these three techniques in live cultured cells. We then explore two applications: monitoring tissue flows on the surface of developing zebrafish embryos, and combinatorial multicolor labeling and sorting of optically defined groups of cells. Photoclick adapters add optical control to cell tagging schemes, with modularity in both tag and cell attachment chemistry.

Spatiotemporal observation of surface plasmon polariton mediated ultrafast demagnetization

Surface plasmons offer a promising avenue in the pursuit of swift and localized manipulation of magnetism for advanced magnetic storage and information processing technology. However, observing and understanding spatiotemporal interactions between surface plasmons and spins remains challenging, hindering optimal optical control of magnetism. Here, we demonstrate the spatiotemporal observation of patterned ultrafast demagnetization dynamics in permalloy mediated by propagating surface plasmon polaritons with sub-picosecond time- and sub-μm spatial- scales by employing Lorentz ultrafast electron microscopy combined with excitation through transient optical gratings. We discover correlated spatial distributions of demagnetization amplitude and surface plasmon polariton intensity, the latter characterized by photo-induced near-field electron microscopy. Furthermore, by comparing the results with patterned ultrafast demagnetization dynamics without surface plasmon polariton interaction, we show that the demagnetization is not only enhanced but also exhibits a spatiotemporal modulation near a spatial discontinuity (plasmonic hot spot). Our findings shed light on the intricate interplay between surface plasmons and spins, offer insights into the optimized control of optical excitation of magnetic materials and push the boundaries of ultrafast manipulation of magnetism.

Fast and high-resolution multimode fiber speckle imaging via optical coherence control

Fast and high-resolution multimode fiber speckle imaging via optical coherence control

Attraction of microbubble at a fiber end face by the solute Marangoni force and its application as a tunable interferometer based on optical control.

In this Letter, we show the attraction of a microbubble at a fiber end face by the solute Marangoni force. The microbubble is formed by partial filling of an ethanol-water mixture in the microcavity that is spliced to the end face of a single-mode fiber. Due to different surface tension of ethanol and water, the uneven temperature gradient induced by a laser causes the non-uniform distribution of ethanol-water molecules on the bubble surface. As a result, the solute Marangoni force that is much larger than the buoyancy is generated and it presses the microbubble against the fiber end face. The microbubble forms a high-quality Fabry-Perot (FP) interferometer, and the interferometric phase can be adjusted by changing the solute Marangoni force that is influenced by the laser power. This Letter gives a new method to achieve a tunable interferometer based on optical control.

Efficient Optical Control of Quantum Tunneling Devices Based on Layered Violet Phosphorus

AbstractElectron tunneling devices attract attention due to their potential applications in integrated circuits, memories, and high‐frequency oscillators. However, limited works are devoted to the optical control of electron tunneling processes. The main reason is the low concentration of photogenerated carriers concerning the equilibrium values in heavy‐doped regions. In this work, violet phosphorus (VP) with a unique bilayer tubular structure supplies an excellent platform for investigating the tunneling mechanisms under photo illumination. A VP‐based vertical tunneling diode made of metal‐insulator‐semiconductor (MIS) stacking is presented. The photogenerated carriers increase the tunneling current by ≈4.2 times through photo illumination, leading to a considerable rectification ratio. In addition, a three‐terminal tunneling field‐effect transistor (TFET) made from VP flake with different thicknesses is also presented. The interband tunneling of electrons results in a tunable negative differential transconductance (NDT) at room temperature. The photoillumination can modulate the onset of the NDT region due to the variation of the density of states with Fermi level alignment in the channel and drain region. These results advance the understanding of electron transport mechanisms in VP‐based tunneling devices, showing great potential for exploiting novel 2D multifunctional devices with interactions between light and carriers’ tunneling.

Optical control of spin waves in hybrid magnonic-plasmonic structures.

Magnonics, which harnesses the unique properties of spin waves, offers promising advancements in data processing due to its broad frequency range, nonlinear dynamics, and scalability for on-chip integration. Effective information encoding in magnonic systems requires precise spatial and temporal control of spin waves. Here, we demonstrate the rapid optical control of spin-wave transport in hybrid magnonic-plasmonic structures. By using thermoplasmonic heating in yttrium iron garnet films integrated with gold nanodisk arrays, we achieve a suppression of spin-wave signals by 20 dB using single laser pulses lasting just a few hundred nanoseconds. Our results reveal a strong correlation between plasmonic light absorption and spin-wave manipulation, as supported by micromagnetic simulations that emphasize the crucial role of magnonic refraction. This study establishes thermoplasmonics as a powerful tool for controlling spin-wave propagation, bridging the fields of magnonics and plasmonics, and paving the way for the development of multifunctional hybrid magnonic devices.

Modular Photoswitchable Molecular Glues for Chemo-Optogenetic Control of Protein Function in Living Cells.

Optogenetic systems using photosensitive proteins and chemically induced dimerization/proximity (CID/CIP) approaches enabled by chemical dimerizers (also termed molecular glues), are powerful tools to elucidate the dynamics of biological systems and to dissect complex biological regulatory networks. Here, we report a versatile chemo-optogenetic system using modular, photoswitchable molecular glues (sMGs) that can undergo repeated cycles of optical control to switch protein function on and off. We use molecular dynamics (MD) simulations to rationally design the sMGs and further expand their scope by incorporating different photoswitches, resulting in sMGs with customizable properties. We demonstrate that this system can be used to reversibly control protein localization, organelle positioning, protein-fragment complementation as well as posttranslational protein levels by light with high spatiotemporal precision. This system enables sophisticated optical manipulation of cellular processes and thus opens up a new avenue for chemo-optogenetics.

Distribution of volumes of plasma channels components between metal granules in working liquids

Introduction. Expanding the capabilities of a number of modern technologies and improving quality of their products require detailed spark and plasma erosion processes control in metal granules layers (MGL). Problem. Traditional measurement of exclusively electrical parameters of these processes, even in the case of multi-electrode systems, provides only a general vision, not allowing monitoring processes in individual plasma channels. Optical control methods make it possible to simultaneously have information about almost every plasma channel in the MGL. The aim of the article is to study the characteristic components of plasma channels arising as a result of the flow of discharge currents in the MGL and to establish the laws of distribution of their volumes and their ratios. Methodology. During the experiments, photographs of plasma channels resulting from the flow of discharge current pulses between Al granules immersed in distilled water were obtained. Using the specialized ToupView program, the volumes of equivalent ellipsoids of rotation, approximating the colored halos and white cores of the plasma channels were determined. Discrete distributions of the volumes of the halo and cores of plasma channels, as well as their ratios were constructed both with and without procedures for screening out «anomalous» results. The efficiency of approximation of discrete distributions obtained in practice by continuous theoretical distributions Weibull, Rosin-Rammler and log-normal was estimated. Results. It is shown that of all the considered theoretical distributions of halo and cores of plasma channels volumes, as well as their ratios, the most adequate is the log-normal one. Originality. For the first time distributions of volumes of halo and cores of plasma channels were studied and their comparative analysis with the size distributions of erosion particles and dimples on the surface of Al granules was given. Practical significance. Taking into account the new obtained results, a technique for constructing distributions of volumes of halo and cores of plasma channels and determining their parameters has been developed. References 53, figures 7, tables 5.

Design considerations for wavefront sensing with self-referencing interferometers in adaptive optics systems

In this work, we show the design and implementation of wavefront sensing with a self-referencing interferometer (SRI). The SRI is developed to aid adaptive optics (AO) control, via deformable mirrors, in correcting wavefront error from atmospheric turbulence in (laser-based) free-space optical communication links. The SRI is used here given its potential to outperform more common wavefront sensors in functioning over weak through strong turbulence conditions. In this study, we identify and analyse the key parameters in the SRI’s optical design and show guiding principles for its subsequent image processing.

Research on Optical Nonreciprocal Control of Cesium Atomic Systems at Room Temperature

Research on Optical Nonreciprocal Control of Cesium Atomic Systems at Room Temperature

Myopia control in the community (optical interventions, biometry, protocol)

In many countries, >50% of university students are myopic, with prevalence rising. Increasing myopia is associated with higher risks of eye disease. Myopia control is necessary because, for example, slowing myopia progression by 1D should reduce the likelihood of a patient developing myopic maculopathy by 40%. Several approaches are available that have slowed progression by ~50% in randomised control trials. In order of decreasing safety/increasing risk of complications, these are spectacle lenses that provide peripheral plus power, contrast reducing spectacle lenses, soft contact lenses providing peripheral plus power, ortho‐keratology, low dose atropine, and repeated low‐level red light therapy (RLRL). Recently, it has been argued that RLRL may not meet safety standards and this will not be considered further.With approximately half of older children/adolescents becoming eligible for myopia control, in most countries it is not feasible for all cases to be managed in hospital ophthalmology units. Increasingly, myopia control is being undertaken in community optical practices and this talk will address best practice, and advantages and disadvantages of this myopia control being undertaken in a community setting.Key considerations are whether community optical practices can provide the breadth of interventions required, and have appropriate skills and equipment. Concerning the breadth of interventions, most clinicians in community optical practices are optometrists and only in a few countries are optometrists able to prescribe therapeutic pharmacological agents. All the optical interventions listed above are potentially available to optometrists. Whether atropine is appropriate depends on the age, clinical characteristics (e.g., rate of progression, axial length, family history), and patient/carer preferences. Optometrists must follow appropriate referral guidelines and make patients aware of alternative approaches to those that they can provide.Concerning the skills required, practitioners should follow recent International Myopia Institute (IMI) guidelines, referring young children with risk factors for syndromic myopia. These require a full history and eye examination, including ophthalmoscopy. Several biometers have been developed for use in myopia control and are increasingly found in optical practices. The evolving debate on the necessity of axial length measurements and/or cycloplegic refraction in myopia control will be considered, noting the 2023 IMI myopia management algorithms.The importance of clinical presentation is emphasised. For example, a child who develops mild myopia at age 12‐14y is likely to be suitable for optical myopia control. If the optometrist has been monitoring for some years reducing hypermetropia progressing to slowly developing myopia then it is questionable whether cycloplegic refraction is required. In contrast, a 5‐7 year‐old who at the first eye examination has moderate myopia requires cycloplegic refraction to exclude pseudo‐myopia.It is concluded that as myopia control is changing from specialist to routine eye care, it must become an essential message for dissemination by all eye care practitioners. As with other commonplace ocular conditions, straightforward cases are likely to be increasingly managed in the community and more complicated cases in secondary care. The lack of state funding, cost of interventions and therefore accessibility will be considered.

Picometre-level surface control of a closed-loop, adaptive X-ray mirror with integrated real-time interferometric feedback.

We provide a technical description and experimental results of the practical development and offline testing of an innovative, closed-loop, adaptive mirror system capable of making rapid, precise and ultra-stable changes in the size and shape of reflected X-ray beams generated at synchrotron light and free-electron laser facilities. The optical surface of a piezoelectric bimorph deformable mirror is continuously monitored at 20 kHz by an array of interferometric sensors. This matrix of height data is autonomously converted into voltage commands that are sent at 1 Hz to the piezo actuators to modify the shape of the mirror optical surface. Hence, users can rapidly switch in closed-loop between pre-calibrated X-ray wavefronts by selecting the corresponding freeform optical profile. This closed-loop monitoring is shown to repeatably bend and stabilize the low- and mid-spatial frequency components of the mirror surface to any given profile with an error <200 pm peak-to-valley, regardless of the recent history of bending and hysteresis. Without closed-loop stabilization after bending, the mirror height profile is shown to drift by hundreds of nanometres, which will slowly distort the X-ray wavefront. The metrology frame that holds the interferometric sensors is designed to be largely insensitive to temperature changes, providing an ultra-stable reference datum to enhance repeatability. We demonstrate an unprecedented level of fast and precise optical control in the X-ray domain: the profile of a macroscopic X-ray mirror of over 0.5 m in length was freely adjusted and stabilized to atomic level height resolution. Aside from demonstrating the extreme sensitivity of the interferometer sensors, this study also highlights the voltage repeatability and stability of the programmable high-voltage power supply, the accuracy of the correction-calculation algorithms and the almost instantaneous response of the bimorph mirror to command voltage pulses. Finally, we demonstrate the robustness of the system by showing that the bimorph mirror's optical surface was not damaged by more than 1 million voltage cycles, including no occurrence of the `junction effect' or weakening of piezoelectric actuator strength. Hence, this hardware combination provides a real time, hyper-precise, temperature-insensitive, closed-loop system which could benefit many optical communities, including EUV lithography, who require sub-nanometre bending control of the mirror form.

An unprecedented double photoexcitation mechanism for photoswitching in conjugated-dienes to trigger physiological processes for photopharmacology.

The optical control of physiological processes with high precision using photoswitches is an emerging strategy for non-invasive diagnosis and therapies, providing innovative solutions to complex biomedical challenges. Light-responsive cyclic conjugated-dienes (cCDs) have long been recognized for their 4π-photocyclization; however, photoswitching behaviour in medium-sized cCDs has recently been reported, representing a pioneering discovery in the field. Reinforced by previous experimental evidence corroborating the Woodward-Hoffmann rules, this report provides insight into the origin of the exotic dual photoexcitation mechanism devised to achieve thermo-reversible photoswitching in large cCDs with cyclodeca-1,3-diene as a prototype. The operation of this mechanism enables access to four distinct photoisomers during a single photoswitching cycle, introducing new dimensions to the functionality of cCDs. Energy profiles calculated using M06-2X align closely with those obtained from DLPNO-CCSD(T), indicating its reliability as a method for predicting these systems, offering a balance between accuracy and computational cost. Time-dependent DFT calculations reveal that the important excitation wavelength of cCDs is significantly red-shifted compared to their photoproducts. The interaction behaviour of these isomers with β-barrel proteins was also analysed using molecular dynamics simulations to rationalize their potential for photopharmacology. The outcomes of the simulations show that photoisomers engage in different interactions inside the cavity, prompting variable conformational changes in the protein. Thus, the versatile architecture of cCDs can expand the toolbox of photoswitch designs for photoresponsive pharmaceuticals with photoisomers serving as mediators for precise reversible optical regulation of biological systems.

ANALYSIS OF THE STRUCTURE OF INTERFERENCE COATINGS FOR THE OPTIMIZATION OF THE PARAMETERS OF NARROWBAND OPTICAL FILTERS

To monitor the parameters of semiconductor layers deposited from solid solutions of A3B5 compounds during the epitaxy, optical control methods are used. The choice of optical monitoring methods is determined by the reactor design, which requires non-contact, fast, and precise measuring of wafer surface parameters. During the growth of epitaxial layers, the deposition of semiconductor compounds causes changes in the optical parameters of the wafer surface. To ensure precise measurements, it is essential to monitor these parameters within a narrow spectral range. In electro-optical monitoring systems, narrowband interference filters are used to select the desired spectrum. However, this type of filters is sensitive to several factors, such as environmental conditions, aging of the coating, and the angle of incidence. As a result, the manufacturing of narrowband optical filters with stable and precisely controlled optical characteristics presents a complex challenge. This article analyzes the impact of various factors on the optical characteristics of interference coatings. Quantitative analysis of these shows that shift of the selected spectral band with central wavelength λmax can approach or even exceed the full width at half maximum (FWHM). These changes in the optical characteristics of narrowband filters lead to a decrease in the accuracy required for optical monitoring during epitaxial processes, which leads to inaccuracies in measurements. The results of this analysis will guide the optimization of thin-film structures used in narrowband optical filters. The study of the shift in the selected band also enables, within certain limits, controlled changes to λmax or the compensation of its shift its shift during regular factor variations. Ultimately, it enables to take these changes into account when designing electro-optical systems for monitoring the epitaxial growth of semiconductor heterostructures, which increases the accuracy and stability of optical measurements in the required accuracy range.

Photoswitchable Diazocine Derivative for Adenosine A3 Receptor Activation in Psoriasis.

Incorporating photoisomerizable moieties within drugs offers the possibility of rapid and reversible light-dependent switching between active and inactive configurations. Here, we developed a photoswitchable adenosine A3 receptor (A3R) agonist that confers optical control on this G protein-coupled receptor through noninvasive topical skin irradiation in an animal model of psoriasis. This was achieved by covalently bonding an adenosine-5'-methyluronamide moiety to a diazocine photochrome, whose singular photoswitching properties facilitated repeated interconversion between a thermally stable, biologically inactive Z agonist form and a photoinduced, pharmacologically active E configuration. As a result, our photoswitchable agonist allowed the precise modulation of A3R function both in vitro and in vivo, which led to a clear light-controlled pharmacotherapeutic effect on mouse skin lesions. This breakthrough not only demonstrates the potential of diazocine photoswitches for in vivo photopharmacology but also paves the way for the development of new strategies for skin-related diseases that require localized and temporally controlled drug action.

Photoinduced Melting of V4O7 Correlated State

AbstractThe compound V4O7 is one of the Magnéli phase (VnO2n − 1, n = 3, 4, …, 9) correlated vanadium oxides with distinct intriguing electronic and structural properties. The possibility to manipulate the phase state of V4O7 on an ultrafast time scale by light makes this material promising for potential applications in photonics, optoelectronics, quantum, and neuromorphic circuit design. In this work, the ultrafast spectroscopy of V4O7 reveals the second‐order nature of the photoinduced insulator‐to‐metal transition, emphasizing electronic and lattice contributions. The findings reveal the influence of the laser excitation level and temperature on these dynamics, providing a comprehensive understanding of V4O7 structural changes and response to external stimuli. The phenomenological model based on the Landau–Ginzburg formalism provides a robust framework for explaining the photoinduced transition dynamics, showing a detailed picture of the light interaction with the electronic and lattice subsystems. This integrated approach significantly enhances the understanding of V4O7 complex behavior upon photoexcitation, opening new possibilities for developing new optoelectronic devices and noninvasive optical control of the phase transition pathways in vanadates.

Optical Control of TRPM8 Channels with Photoswitchable Menthol

Transient receptor potential melastatin 8 (TRPM8) channels are well known as sensors for cold temperatures and cooling agents such as menthol and icilin and these channels are tightly regulated by the membrane lipid phosphoinositol‐4,5‐bisphosphate (PIP2). Since TRPM8 channels emerged as promising drug targets for treating pain, itching, obesity, cancer, dry eye disease, and inflammation, we aimed at developing a high‐precision TRPM8 channel activator, to achieve spatiotemporal control of TRPM8 activity with light. In this study, we designed, synthesized and characterized the first photoswitchable TRPM8 activator azo‐menthol (AzoM). AzoM enables optical control of endogenously and heterologously expressed TRPM8 channels with UV and blue light which is demonstrated by performing patch‐clamp experiments. Moreover, AzoM facilitates the reliable determination of activation, inactivation, and deactivation kinetics thereby providing further insights into the channel gating. Using AzoM, the specific roles of individual amino acids for AzoM or PIP2 binding and for sensitization by PIP2 can be elucidated. Altogether, AzoM represents as a high‐precision pharmaceutical tool for reversible control of TRPM8 channel function that enhances our biophysical understanding of TRPM8 channels and holds the potential to support the development of novel pharmaceuticals.

Ultrafast Control over Stiffening and Softening of Coherent Interlayer Coupling in WSe2/WS2 Heterobilayers.

Twisted van der Waals heterostructures have led to emerging layer-dependent correlated physics in moiré potentials. While optoelectronic controls over interlayer electronic coupling have been reported, the concomitant interlayer vibration has not yet been controlled. Here, we report experimental evidence of ultrafast optical control over the amplitude and oscillation period of interlayer breathing phonons in WSe2/WS2 heterobilayers. Femtosecond optical excitation above the Mott density in gate-tuned devices shows as large as 10% changes of stiffening and softening amplitude of coherent phonons. A theoretical model, incorporating both Buckingham and Hartree energies, is presented to elucidate the impact of charge-separated carriers generated by photoexcitation on phonon dynamics. This work, therefore, provides insights for extending optoelectronic engineering into the coherent phonons in moiré systems.