Light Manipulation Research Articles

Integrated Pockels Modulators on Silicon Photonics Platform

AbstractElectro‐optic (EO) modulators are essential components in various fields, including optical communication, free‐space communication, microwave photonics, sensing, and light detection and ranging. The EO modulation enables the fast conversion of electric signals into optical signals, facilitating the precise manipulation of light. With advancements in fabrication processing techniques, next‐generation integrated EO modulators have demonstrated substantial improvements in modulation efficiency, bandwidth, and footprint. Here, the latest research progress in integrated EO modulation, focusing on the principle of the Pockels effect, key modulation metrics, novel EO thin‐film material platforms, and innovative device architectures is overviewed. Finally, it is evaluated different schemes and provide perspectives on future trends in developing integrated EO modulators, highlighting both the advantages and challenges of integrated EO modulation, including waveguide and electrode engineering, integrated methods, and other applications for large‐scale photonic integrated circuits.

Light-driven integration of diazotroph-derived nitrogen in euphotic nitrogen cycle

The bioavailable nitrogen fixed by diazotrophs is critical for sustaining productivity in the oligotrophic ocean. Despite this, understanding how diazotroph-derived nitrogen integrates into the nitrogen cycle within the euphotic zone remains unknown. Here, we investigated nitrogen fixation rates in the particulate and dissolved fractions within the euphotic zone of the North Pacific Subtropical Gyre. Our findings reveal the proportion of nitrogen fixation rates in the dissolved fraction increases with depth. Light manipulation experiments uncover that reduced light levels can stimulate the net release of diazotroph-derived nitrogen, aligning with our depth-related observations. Furthermore, we identify two distinct transfer pathways vertically associated with light-driven ecological niches. Specifically, the released diazotroph-derived nitrogen is transferred to non-diazotrophic plankton in the upper layers. Meanwhile, in the lower layers, it contributes to the nitrification process. Our results underscore the high bioavailability of diazotroph-derived nitrogen and its rapid integration into the nitrogen cycle through multiple pathways within the well-lit ocean.

A Review for Design, Mechanism, Fabrication, and Application of Magnetically Responsive Microstructured Functional Surface

Abstract Magnetically responsive microstructured functional surface (MRMFS), capable of dynamically and reversibly switching the surface topography under magnetic actuation, provide a wireless, noninvasive, and instantaneous way for accurate control of microscale engineered surface. In the last decade, many studies have been conducted to design and optimize MRMFSs for diverse applications, and great progresses have been accomplished. This review comprehensively presents recent advancements and the potential prospects in MRMFSs. We firstly classify MRMFSs into 1D linear array MRMFSs, 2D planar array MRMFSs, and dynamic self-assembly MRMFSs based on their morphology. Subsequently, an overview of three deformation mechanisms including magnetically actuated bending deformation, magnetically driven rotational deformation, and magnetically induced self-assembly deformation are provided. Four main fabrication strategies employed to create MRMFSs are summarized including replica molding, magnetization-induced self-assembly, laser cutting, and ferrofluid-infused method. Furthermore, the applications of MRMFS in droplet manipulation, solid transport, information encryption, light manipulation, triboelectric nanogenerators, and soft robotics are presented. Finally, the current challenges that limit the practical applications of MRMFSs are discussed, and the future development of MRMFSs is proposed.

Deep Learning‐Based Variational Autoencoder for Classification of Quantum and Classical States of Light

AbstractAdvancements in optical quantum technologies have been enabled by the generation, manipulation, and characterization of light, with identification based on its photon statistics. However, characterizing light and its sources through single photon measurements requires efficient detectors and longer measurement times to obtain high‐quality photon statistics. Here, a deep learning‐based variational autoencoder (VAE) method is introduced for classifying single photon added coherent state (SPACS), single photon added thermal state (SPATS), and mixed states between coherent and SPACS as well as between thermal and SPATS of light. The semi‐supervised learning‐based VAE efficiently maps the photon statistics features of light to a lower dimension, enabling quasi‐instantaneous classification with low average photon counts. The proposed VAE method is robust and maintains classification accuracy in the presence of losses inherent in an experiment, such as finite collection efficiency, non‐unity quantum efficiency, finite number of detectors, etc. Additionally, leveraging the transfer learning capabilities of VAE enables successful classification of data of any quality using a single trained model. It is envisioned that such a deep learning methodology will enable better classification of quantum light and light sources even in poor detection.

Stretchable plasmonic metasurfaces for deformation monitoring

Abstract Metasurfaces have recently gained significant attention due to the strong capacity in light field manipulation. However, most traditional metasurfaces are fabricated on rigid substrates, which fix their functionality after fabrication and limit their applications in dynamic measurement fields. In this work, we designed and fabricated a silver metasurface embedded in a stretchable substrate for sensing applications. This metasurface can generate different point cloud patterns under varying stretch ratios when illuminated by a laser beam. By collecting and analyzing the patterns, we can precisely reconstruct the deformation of the metasurface. Furthermore, the sample exhibits excellent performance under incident light of various wavelengths. These results pave the way for developing microdevices with novel capabilities based on flexible metamaterials.

Driven-dissipative phases and dynamics in non-Markovian nonlinear photonics

Interactions between photons (nonlinearities) enable a powerful form of control over the state of light. This control has enabled technologies such as light sources at new wavelengths, ultra-short optical pulses, frequency-comb metrology systems, even quantum light sources. Common to a wide variety of nonlinear optical technologies is an equilibrium between an energy source, such as an external laser, and dissipation, such as radiation loss or absorption. In the vast majority of these systems, the coupling between the system and the outside world (which leads to loss) is well described as “Markovian,” meaning that the outside world has no memory of its past state. In this work, we introduce a class of driven-dissipative systems in which a nonlinear cavity experiences non-Markovian coupling to the outside world. In the classical regime, we show that these non-Markovian cavities can have extremely low thresholds for nonlinear effects, as well as self-pulsing instabilities at THz rates, and rich phase diagrams with alternating regions of stability and instability. In the quantum regime, we show how these systems, when implemented on state-of-the-art platforms, can enable generation of strongly squeezed cavity states with intensity fluctuations that can be more than 15 dB below the classical limit, in contrast to the Markovian driven-dissipative cavity, in which the limit is 3 dB. In the regime of few-photon nonlinearity, such non-Markovian cavities can enable a deterministic protocol to generate Fock states of high order, which are long-desired, but still elusive at optical frequencies. We expect that exploiting non-Markovian couplings in nonlinear optics should in the future lead to even richer possibilities than those discussed here for both classical and quantum light manipulations.

Experimental analysis of Airy beam self-localization in nematic liquid crystals.

This study employs experimental demonstration of finite energy Airy beam (AB) propagation in nematic liquid crystals (NLCs), highlighting the reorientational optical nonlinearity that induces the generation of off-shoot solitons (OSS). The outcomes of our investigation indicate that the direction of the OSS is greatly influenced by optical power and the beam's walk-off, providing novel perspectives on light manipulation in NLCs. These findings significantly advance understanding Airy beam behavior in nonlinear materials and propose potential applications in photonic tools.

7503 Light Composition Alters Feline Stress in a Shelter Environment

Abstract Disclosure: A.M. Yaw: None. M.E. Gardella: None. J. Jacobs: None. H.M. Hoffmann: None. Millions of cats enter animal shelters each year. Unfortunately, due to high numbers of cats entering shelters and limited physical housing space, over 50% of healthy and adoptable cats with extended shelter stays are euthanized yearly. While animal shelters are essential for keeping cats safe from unfit living conditions, they are a stressful environment. High stress in cats increases health risks and undesirable behaviors and is associated with reduced adoptions. Given the role of light in regulating hormonal stress responses and behavior, we partnered with a Midwestern animal control and shelter to evaluate how light intensity and light composition impact feline behavior and urinary cortisol levels in 123 domestic cats (Felis catus; 65 male and 58 female). The impact of three lighting conditions, white, dim, and orange (blue-depleted) light, were evaluated for the first 5-6 days following admittance into the shelter. Individually housed adults (8 months-10 years) were outfitted with PetPace Smart Collars to evaluate locomotor activity, and cat stress was evaluated daily through urine samples and a behavioral approach test. All data were analyzed by experimenters who were blind to the groups and tested via one or two-way ANOVA or repeated measures mixed-effects model with Geisser-Greenhouse correction. Urinary cortisol levels were dependent on both light quality and day in shelter, where cats under orange light had reduced cortisol on days 4-5 in the shelter compared to cats in standard lighting. Light quality also altered cat hiding behavior, such that the percentage of cats hiding was increased on dim light compared to both standard and orange light. A novel behavioral approach task found reduced cat stress on days 4-5 in standard and orange light; however, dim light increased cat stress on day 5 in shelter. All cats exhibited circadian rhythms in locomotor activity with periods ranging from 21.33-35.67h independent of light condition and day in shelter, and locomotor activity increased on days 3-4 compared to day 2 in the shelter, with no effect of light condition. There were no sex differences in in hiding, PetPace activity, or cat stress scores under any light condition; however, females displayed increased urinary cortisol levels compared to males in standard, but not dim or orange, light. This shows for the first time that room light manipulation can help shelters enact easy and inexpensive changes that make the adjustment period shorter and less stressful for incoming cats which will improve animal wellbeing. Presentation: 6/1/2024

Germanium metalens for longwave infrared applications

Metalenses represent a paradigm shift in optics, offering unprecedented control over light manipulation. This study focuses on the design optimization of a polarization-insensitive germanium (Ge) metalens operating in the longwave infrared (LWIR) regime. Employing rigorous coupled-wave analysis (RCWA) and finite-difference time-domain (FDTD) simulations, a metalens with 1mm focal length was designed using nanopillars with 3.5µm height and radius ranging from 0.55µm to 1.2µm. Then, the impact of lattice size and numerical aperture (NA) on lens performance was investigated. The results indicate that smaller lattices allow finer phase control and enhanced transmittance stability across the phase profile if significant coupling effects are not verified. As the NA increases, the focal spot size decreases, albeit with diminishing returns towards the diffraction limit. To the best of our knowledge, it is the first work that shows high focal efficiency (~80%) across multiple NA’s for a LWIR metalens with a diameter under 1100µm. The proposed metalens is compatible with complementary metal-oxide-semiconductor (CMOS) technology and supports low-cost manufacturing.

Unravelling the Spectrum: Recent Advances in the Synthesis of Phosphorous–Selenium Bonded Compounds

AbstractThe review delves into a rich tapestry of methodologies, spanning from the utilization of metals to the manipulation of light, and from electrochemical pathways to additive‐free approaches. Its aim is to meticulously compile and elucidate these diverse pathways, providing comprehensive insights into the strategies and methodologies utilized for synthesizing these compounds. By undertaking this exploration, its goal is to shed light on the intricate techniques employed in this field, consequently driving notable progress across disciplines ranging from biochemistry to medicinal research.

Exotic spin-Hall effect in non-Hermitian optical systems

Abstract We systematically explore the origin and evolution of the exceptional points (EP) when a light beam is scattered by a parity-time (PT)-symmetric system using a scattering matrix approach and a full-wave theory. It is demonstrated that the PT-symmetric system switches between symmetry and symmetry-breaking phases at the EPs, giving rise to singular features in the Fresnel coefficients and causing the spin-Hall effect (SHE) near the EPs to exhibit anomalous features such as significantly enhanced transverse spin-Hall shifts and additional in-plane spin-Hall shifts. This exotic SHE can be explained by the significant beam intensity distortion caused by the destructive interference between the spin-maintained normal modes and the spin-reversed abnormal modes in the scattered light. This phenomenon can further be understood in terms of vortex mode decomposition, wherein it can be interpreted as the competition and superposition of three vortex modes with topological charges of −1, 0, and 1, respectively. These findings elucidate the mechanism of the unusual SHE around the EPs and offer potential avenues for EP-based sensing and structured light manipulation.

Au Nanorings/TiO2 NPs@MXene-Based Metasurfaces with a Magnetic Mirror-Modulated ECL Strategy for Extracellular Vesicle Detection.

A metasurface as an artificial electromagnetic structure can concentrate optical energy into nanometric volumes to strongly enhance the light-matter interaction, which has been becoming a powerful platform for optical sensing, nonlinear effects, and quantum optics. Herein, we developed a novel hybrid plasmonic-dielectric metasurface consisting of Au nanorings (Au NRs) and TiO2 nanoparticles derived from MXene (TiO2 NPs@MXene). The hybrid metasurface simultaneously benefited from the high near-field enhancement effect of plasmonic materials and the low loss of dielectric materials. Furthermore, the optical modulation efficiency of the hybrid metasurface can be regulated by a magnetic mirror configuration. The magnetic mirror acted like a mirror, confining the electrons to a limited region and increasing the density of the surface plasmon. Moreover, the electrochemiluminescence (ECL) of the Cu2BDC metal-organic framework (Cu2BDC-MOF) served as a light source for the Au NRs/TiO2 NPs@MXene metasurface. Due to the exceptional light manipulation capability of the hybrid metasurface and the coordination of the magnetic mirror, the isotropic ECL signal can be dynamically amplified and converted into polarized emission. Finally, a metasurface-regulated ECL (MECL)-based biosensor with a dual-positive membrane protein recognition strategy was developed for the accurate identification of gastric cancer-derived extracellular vesicles. The novel MECL research opened up a new route in the realization of dynamically tunable metasurfaces for optical sensing and novel nanophotonic devices.

Achromatic Silicon Photonic Waveguide Lenses for Ultra‐Broadband Multimode Spot‐Size Conversion

AbstractThe rapid development of silicon photonics inspired the emergence of on‐chip geometric optics. As one of the most crucial elements, waveguide‐lenses have attracted much attention. Nevertheless, waveguide‐lenses often suffer from large chromatism due to the strong waveguide dispersion, especially for the cases with multiple guided‐modes. In this paper, achromatic waveguide‐lenses available for multimode photonics are proposed and are further utilized for realizing multimode spot size converters (MSSCs) as an example. The present MSSC shows low excess losses < 0.4 dB and low inter‐mode crosstalks <−14 dB within an ultra‐broad bandwidth of 1450–1650 nm, which is realized for the first time by comprising a positive waveguide‐lens and a negative waveguide‐lens. In addition, the present MSSC is applied successfully for realizing high‐performance multimode waveguide corner‐bends. To the best of the knowledge, the proposed MSSC is the unique one with an ultra‐compact footprint and the largest bandwidth for low crosstalks as well as low losses, indicating that on‐chip geometric optics potentially provides a new perspective for on‐chip light manipulation desired in various applications.

Фотонные кристаллы: оптимизация характеристик и перспективы оптических приложений

Background: Photonic crystals (PCs) have emerged as a new material for light manipulation, providing unprecedented control over light-matter interaction. This unique capacity is due to their periodic dielectric structure, which may produce photonic band gaps that impact photon transmission. Objective: The article summarizes current advances in photonic crystal design and use, focusing on their significance in creating next-generation optical systems. Methods: The article performed a complete literature analysis, concentrating on the most recent PC production and characterization approaches. Innovative techniques like 3D printing, nanoimprint lithography, self-assembly, and advanced computational modelling were studied in depth to optimize their optical characteristics. Results: Recent studies show that PC manufacturing accuracy has increased significantly, allowing for more effective light manipulation and enhanced optical device functioning. Applications such as ultrasensitive sensors, improved optical fibers, and innovative laser designs demonstrate PCs' rising value. Conclusion: The ongoing advancement of photonic crystal technology is laying a solid basis for the next generation of optical devices. These developments improve existing applications and provide opportunities to investigate new functionality in optical and other electromagnetic systems. Incorporating PCs into numerous technical sectors holds the prospect of significant advances in both commercial and scientific fields.

Interplay of Circularly Polarized Light with Molecular and Structural Chirality: Chiral Lanthanide Complexes and Cellulose Nanocrystals

AbstractThe interaction of circularly polarized (CP) light with chiral matter at different scales opens several possibilities of light manipulation in photonic and electronic devices. Here it is shown that in a multilayer architecture, it is possible to take advantage of the polarization‐selective reflection of the nematic arrangement of cellulose nanocrystals and the strong intrinsic CP luminescence (CPL) of the various bands of chiral Eu complexes. In this way, both the intrinsic CPL and total emission of the complex are modified depending on the enantiomer applied and on the detection geometry. This concept may apply for polarization control in electronic and photonic devices and polarized optical cavities.

Deep-trap ultraviolet persistent phosphor for advanced optical storage application in bright environments

Extensive research has been conducted on visible-light and longer-wavelength infrared-light storage phosphors, which are utilized as promising rewritable memory media for optical information storage applications in dark environments. However, storage phosphors emitting in the deep ultraviolet spectral region (200–300 nm) are relatively lacking. Here, we report an appealing deep-trap ultraviolet storage phosphor, ScBO3:Bi3+, which exhibits an ultra-narrowband light emission centered at 299 nm with a full width at half maximum (FWHM) of 0.21 eV and excellent X-ray energy storage capabilities. When persistently stimulated by longer-wavelength white/NIR light or heated at elevated temperatures, ScBO3:Bi3+ phosphor exhibits intense and long-lasting ultraviolet luminescence due to the interplay between defect levels and external stimulus, while the natural decay in the dark at room temperature is extremely weak after X-ray irradiation. The impact of the spectral distribution and illuminance of ambient light and ambient temperature on ultraviolet light emission has been studied by comprehensive experimental and theoretical investigations, which elucidate that both O vacancy and Sc interstitial serve as deep electron traps for enhanced and prolonged ultraviolet luminescence upon continuous optical or thermal stimulation. Based on the unique spectral features and trap distribution in ScBO3:Bi3+ phosphor, controllable optical information read-out is demonstrated via external light or heat manipulation, highlighting the great potential of ScBO3:Bi3+ phosphor for advanced optical storage application in bright environments.

First-principles investigation of spin characteristics and thermoelectric properties in Ba2SmMoO6 and Ba2EuMoO6 double perovskites

This investigation employs first-principles calculations with the Generalized Gradient Approximation (GGA) and modified Becke-Johnson (mBJ) exchange-correlation functionals, employing the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method. The main objective is to investigate the double perovskites Ba2SmMoO6 and Ba2EuMoO6. We conduct a thorough analysis of the structural, electrical, magnetic, thermoelectric and optical properties of these materials. Both compounds are stable in ferromagnetic phase, according to structural studies. Ba2SmMoO6 has a 3.80 eV energy gap, aligned with the W-X direction, which exhibits half-metallic behavior. On the other hand, Ba2EuMoO6 has a 3.03 eV energy gap that is directly aligned with the X-X direction, using mBJ-GGA. Magnetic investigation revealed a total spin magnetic moment of 7 μB for Ba2EuMoO6, mainly due to Eu (5.98 μB) and 6 μB for Ba2SmMoO6, mainly due to Sm (4.53 μB). It was found that both materials have high Seebeck coefficients and electrical conductivities at high temperatures, with performance improving with temperature. However, the figure of merit (ZT) approaches a value of one, indicating their potential for use in thermoelectric applications at high temperatures. Ba2SmMoO6 and Ba2EuMoO6 are identified as highly favourable options for effective thermoelectric devices. The high UV absorption, the unique refractive and reflective properties offer potential in photonics, optical coatings, and other fields requiring precise light manipulation.

On chip control and detection of complex SPP and waveguide modes based on plasmonic interconnect circuits

Abstract Optical interconnects, leveraging surface plasmon modes, are revolutionizing high-performance computing and AI, overcoming the limitations of electrical interconnects in speed, energy efficiency, and miniaturization. These nanoscale photonic circuits integrate on-chip light manipulation and signal conversion, marking significant advancements in optoelectronics and data processing efficiency. Here, we present a novel plasmonic interconnect circuit, by introducing refractive index matching layer, the device supports both pure SPP and different hybrid modes, allowing selective excitation and transmission based on light wavelength and polarization, followed by photocurrent conversion. We optimized the coupling gratings to fine-tune transmission modes around specific near-infrared wavelengths for effective electrical detection. Simulation results align with experimental data, confirming the device’s ability to detect complex optical modes. This advancement broadens the applications of plasmonic interconnects in high-speed, compact optoelectronic and sensor technologies, enabling more versatile nanoscale optical signal processing and transmission.

Spatiotemporal hologram

Spatiotemporal structured light has opened up new avenues for optics and photonics. Current spatiotemporal manipulation of light mostly relies on phase-only devices such as liquid crystal spatial light modulators to generate spatiotemporal optical fields with unique photonic properties. However, simultaneous manipulation of both amplitude and phase of the complex field for the spatiotemporal light is still lacking, limiting the diversity and richness of achievable photonic properties. In this work, a simple and versatile spatiotemporal holographic method that can arbitrarily sculpt the spatiotemporal light is presented. The capabilities of this simple yet powerful method are demonstrated through the generation of fundamental and higher-order spatiotemporal Bessel wavepackets, spatiotemporal crystal-like and quasi-crystal-like structures, and spatiotemporal flat-top wavepackets. Fully customizable spatiotemporal wavepackets will find broader application in investigating the dynamics of spatiotemporal fields and interactions between ultrafast spatiotemporal pulses and matters, unveiling previously hidden light-matter interactions and unlocking breakthroughs in photonics and beyond.

Photo- and exchange-field controlled spin and valley polarized transport in a normal/antiferromagnetic/normal (N/AF/N) junction based on transition metal dichalcogenides

Abstract We theoretically investigate spin- and valley-polarized transport within a normal/antiferromagnetic/normal (N/AF/N) junction based on transition metal dichalcogenides (TMDs), under the influence of off-resonance circularly polarized light and gate voltage. Antiferromagnetism modulates spin states and the effective gap, reducing the spin gap for one state while increasing it for the opposite, resulting in a broad spin polarization and a controlled gap. Off-resonance circularly polarized light adjusts the valley degree of freedom and the effective gap, providing a wide range of valley polarization. Harnessing the strong spin- orbit coupling in TMDs enables perfect spin-valley polarization in the proposed junction across a wide range of Fermi energies through AF and/or off-resonance light manipulation. AF manipulation effectively narrows the band gap of TMDs at lower light energies, enhancing potential applications of the proposed junction for spin-valley filtering.