Michelson Interferometric Methods for Full Optical Complex Convolution.

Optical real-time data processing is advancing fields like tensor algebra acceleration, cryptography, and digital holography. This technology offers advantages such as reduced complexity through optical fast Fourier transform and passive dot-product multiplication. In this study, the proposed Reconfigurable Complex Convolution Module (RCCM) is capable of independently modulating both phase and amplitude over two million pixels.

Near-Field Observation of the Photonic Spin Hall Effect.

The photonic spin Hall effect, referring to the spatial separation of photons with opposite spins due to spin-orbit interactions, has enabled potential for various spin-sensitive applications and devices. Here, using scattering-type near-field scanning optical microscopy, we observe spin-orbit interactions introduced by a subwavelength semiring antenna integrated in a plasmonic circuit. Clear evidence of unidirectional excitation of surface plasmon polaritons is obtained by direct comparison of the amplitude- and phase-resolved near-field maps of the plasmonic nanocircuit under excitation with photons of opposite spin states coupled to a plasmonic nanoantenna.

Electrical programmable multilevel nonvolatile photonic random-access memory.

Photonic Random-Access Memories (P-RAM) are an essential component for the on-chip non-von Neumann photonic computing by eliminating optoelectronic conversion losses in data links. Emerging Phase-Change Materials (PCMs) have been showed multilevel memory capability, but demonstrations still yield relatively high optical loss and require cumbersome WRITE-ERASE approaches increasing power consumption and system package challenges. Here we demonstrate a multistate electrically programmed low-loss nonvolatile photonic memory based on a broadband transparent phase-change material (Ge2Sb2Se5, GSSe) with ultralow absorption in the amorphous state.

Self-Powered SbTe/MoS Heterojunction Broadband Photodetector on Flexible Substrate from Visible to Near Infrared.

Van der Waals (vdWs) heterostructures, assembled by stacking of two-dimensional (2D) crystal layers, have emerged as a promising new material system for high-performance optoelectronic applications, such as thin film transistors, photodetectors, and light-emitters. In this study, we showcase an innovative device that leverages strain-tuning capabilities, utilizing a MoS/SbTe vdWs p-n heterojunction architecture designed explicitly for photodetection across the visible to near-infrared spectrum. These heterojunction devices provide ultra-low dark currents as small as 4.

Self-powered broadband photodetector based on MoS/SbTe heterojunctions: a promising approach for highly sensitive detection.

Topological insulators have shown great potential for future optoelectronic technology due to their extraordinary optical and electrical properties. Photodetectors, as one of the most widely used optoelectronic devices, are crucial for sensing, imaging, communication, and optical computing systems to convert optical signals to electrical signals. Here we experimentally show a novel combination of topological insulators (TIs) and transition metal chalcogenides (TMDs) based self-powered photodetectors with ultra-low dark current and high sensitivity.

Programmable chalcogenide-based all-optical deep neural networks.

We demonstrate a passive all-chalcogenide all-optical perceptron scheme. The network's nonlinear activation function (NLAF) relies on the nonlinear response of GeSbTe to femtosecond laser pulses. We measured the sub-picosecond time-resolved optical constants of GeSbTe at a wavelength of 1500 nm and used them to design a high-speed GeSbTe-tuned microring resonator all-optical NLAF.

100 GHz micrometer-compact broadband monolithic ITO Mach-Zehnder interferometer modulator enabling 3500 times higher packing density.

Electro-optic modulators provide a key function in optical transceivers and increasingly in photonic programmable application-specific integrated circuits (ASICs) for machine learning and signal processing. However, both foundry-ready silicon-based modulators and conventional material-based devices utilizing lithium-niobate fall short in simultaneously providing high chip packaging density and fast speed. Current-driven ITO-based modulators have the potential to achieve both enabled by efficient light-matter interactions.

A Chirality-Based Quantum Leap.

There is increasing interest in the study of chiral degrees of freedom occurring in matter and in electromagnetic fields. Opportunities in quantum sciences will likely exploit two main areas that are the focus of this Review: (1) recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterials and (2) rapidly evolving nanophotonic strategies designed to amplify chiral light-matter interactions. On the one hand, the CISS effect underpins the observation that charge transport through nanoscopic chiral structures favors a particular electronic spin orientation, resulting in large room-temperature spin polarizations.

Integrated ultra-high-performance graphene optical modulator.

With the increasing need for large volumes of data processing, transport, and storage, optimizing the trade-off between high-speed and energy consumption in today's optoelectronic devices is getting increasingly difficult. Heterogeneous material integration into silicon- and nitride-based photonics has showed high-speed promise, albeit at the expense of millimeter-to centimeter-scale footprints. The hunt for an electro-optic modulator that combines high speed, energy efficiency, and compactness to support high component density on-chip continues.

Electrically tunable metasurface by using InAs in a metal-insulator-metal configuration.

The ability of modulating optical properties at a lateral subwavelength scale is of crucial importance due to its potential applications for wide-angle holographic displays, optical communications, and interferometric sensors. Here, we present an electrically tunable metasurface whose optical properties can be element-wise controlled at the lateral subwavelength scale in the mid-infrared wavelength regime. Our proposed device facilitates an -doped InAs layer as a dynamic-tunable layer, and the charge carrier concentration inside the InAs layer is tailored by external gate biases.

Quantifying Information via Shannon Entropy in Spatially Structured Optical Beams.

While information is ubiquitously generated, shared, and analyzed in a modern-day life, there is still some controversy around the ways to assess the amount and quality of information inside a noisy optical channel. A number of theoretical approaches based on, e.g.

On-chip nanophotonic broadband wavelength detector with 2D-Electron gas: Nanophotonic platform for wavelength detection in visible spectral region.

Miniaturized, low-cost wavelength detectors are gaining enormous interest as we step into the new age of photonics. Incompatibility with integrated circuits or complex fabrication requirement in most of the conventionally used filters necessitates the development of a simple, on-chip platform for easy-to-use wavelength detection system. Also, intensity fluctuations hinder precise, noise free detection of spectral information.

Symmetry perception with spiking neural networks.

Mirror symmetry is an abundant feature in both nature and technology. Its successful detection is critical for perception procedures based on visual stimuli and requires organizational processes. Neuromorphic computing, utilizing brain-mimicked networks, could be a technology-solution providing such perceptual organization functionality, and furthermore has made tremendous advances in computing efficiency by applying a spiking model of information.

Heterogeneously integrated ITO plasmonic Mach-Zehnder interferometric modulator on SOI.

Densely integrated active photonics is key for next generation on-chip networks for addressing both footprint and energy budget concerns. However, the weak light-matter interaction in traditional active Silicon optoelectronics mandates rather sizable device lengths. The ideal active material choice should avail high index modulation while being easily integrated into Silicon photonics platforms.

Generation of helical topological exciton-polaritons.

Topological photonics in strongly coupled light-matter systems offer the possibility for fabricating tunable optical devices that are robust against disorder and defects. Topological polaritons, i.e.

Silicon nitride grating based planar spectral splitting concentrator for NIR light harvesting.

We design a multi-layered solar spectral splitting planar concentrator for near infrared (NIR) light energy harvesting application. Each layer includes a silicon nitride based subwavelength diffraction grating on top of a glass substrate that is optimized to diffract the incoming solar radiation in a specific band from a broad spectral band (700-1400 nm in the NIR region) into guided modes propagating inside the glass substrate. The steep diffraction angle due to subwavelength grating results in concentrated light at the edge of each layer where it is then converted to electricity using a photovoltaic cell.

Biodegradable and Insoluble Cellulose Photonic Crystals and Metasurfaces.

The replacement of plastic with eco-friendly and biodegradable materials is one of the most stringent environmental challenges. In this respect, cellulose stands out as a biodegradable polymer. However, a significant challenge is to obtain biodegradable materials for high-end photonics that are robust in humid environments.

CLEAR: A Holistic Figure-of-Merit for Post- and Predicting Electronic and Photonic-based Compute-system Evolution.

Continuing demands for increased computing efficiency and communication bandwidth have pushed the current semiconductor technology to its limit. This led to novel technologies with the potential to outperform conventional electronic solutions such as photonic pre-processors or accelerators, electronic-photonic hybrid circuits, and neural networks. However, the efforts made to describe and predict the performance evolution of compute-performance fall short to accurately predict and thereby explain the actually observed development pace with time; that is all proposed metrics eventually deviate from their development trajectory after several years from when they were originally proposed.

Observation and Active Control of a Collective Polariton Mode and Polaritonic Band Gap in Few-Layer WS Strongly Coupled with Plasmonic Lattices.

Two-dimensional semiconductors host excitons with very large oscillator strengths and binding energies due to significantly reduced carrier screening. Two-dimensional semiconductors integrated with optical cavities are emerging as a promising platform for studying strong light-matter interactions as a route to explore a variety of exotic many-body effects. Here, in few-layered WS coupled with plasmonic nanoparticle lattices, we observe the formation of a collective polaritonic mode near the exciton energy and the formation of a complete polariton band gap with energy scale comparable to the exciton-plasmon coupling strength.

A Spectrally Tunable Dielectric Subwavelength Grating based Broadband Planar Light Concentrator.

Energy consumption of buildings is increasing at a rapid pace due to urbanization, while net-zero energy buildings offer a green and sustainable solution. However, limited rooftop availability on multi-story buildings poses a challenge for large-scale integration of photovoltaics. Conventional silicon solar panels block visible light making them unfeasible to cover all the surfaces of a building.

Towards integrated metatronics: a holistic approach on precise optical and electrical properties of Indium Tin Oxide.

The class of transparent conductive oxides includes the material indium tin oxide (ITO) and has become a widely used material of modern every-day life such as in touch screens of smart phones and watches, but also used as an optically transparent low electrically-resistive contract in the photovoltaics industry. More recently ITO has shown epsilon-near-zero (ENZ) behavior in the telecommunication frequency band enabling both strong index modulation and other optically-exotic applications such as metatronics. However, the ability to precisely obtain targeted electrical and optical material properties in ITO is still challenging due to complex intrinsic effects in ITO and as such no integrated metatronic platform has been demonstrated to-date.

Neuromorphic photonics with electro-absorption modulators.

Photonic neural networks benefit from both the high-channel capacity and the wave nature of light acting as an effective weighting mechanism through linear optics. Incorporating a nonlinear activation function by using active integrated photonic components allows neural networks with multiple layers to be built monolithically, eliminating the need for energy and latency costs due to external conversion. Interferometer-based modulators, while popular in communications, have been shown to require more area than absorption-based modulators, resulting in a reduced neural network density.