We studied dispersion in Rhodamine laser dyes in the Kretschmann geometry and found (i) multi-branch “staircase” dispersion curves in singly doped and double doped PMMA polymer, (ii) emergence of the new dispersion “fork” branch, (iii) unparallel dispersion and coupling in the mixture of two different dyes, and (iv) effect of high dye concentration on strong coupling without metal.

Surface-enhanced infrared absorption (SEIRA) spectroscopy holds significant promise for chemical detection as it enables direct identification of distinct vibrational fingerprints of molecules. Traditionally, SEIRA has been exploited through the use of tailored metallic nanoantennas, which are burdened by high losses in the mid infrared and costly nanofabrication techniques. In this work, we introduce

The Hong–Ou–Mandel (HOM) effect, an effective two-photon interference phenomenon, is a cornerstone of quantum optics and a key tool for linear optical quantum information processing. While the HOM effect has been extensively studied both theoretically and experimentally for various photonic quantum states, particularly in the spectral domain, detailed overviews of its behaviour for structured photons

In the strong light–matter coupling regime, the transmission properties of metasurfaces have a remarkable similarity to those of typical two-level systems. In this work, we explore the absorption spectra of a metasurface coupled to a quantum phonon bath using the time-dependent variational principle and the flexible multi-D2 Davydov trial states. In the weak light–matter coupling regime, phonon coupling

Common techniques for measuring refractive indices, such as ellipsometry and goniometry, are ineffective for van der Waals crystal flakes because of their high anisotropy and small, micron-scale, lateral size. To address this, we employ near-field optical microscopy to analyze the guided optical modes within these crystals. By probing these modes in MoS2 flakes with subwavelength spatial resolution

The interaction between free electrons and laser-induced near-fields provides a platform to study ultrafast processes and quantum phenomena while enabling precise manipulation of electron wavefunctions through linear and orbital momentum transfer. Here, by introducing phase offset between two orthogonally polarized laser pulses exciting a gold nanorod, we generate a rotating plasmonic near-field dipole

Infrared windows-enabled infrared inspection has significant applications in both civilian and military domains. However, the static and indiscriminate transparency across the visible to infrared regions renders them vulnerable to potential laser damage. In this study, we construct a dynamic infrared optical switch based on a vanadium dioxide (VO2)–Al metasurface structure. The phase transition of

Ultra-silicon-rich nitride Bragg gratings provide a powerful platform for precise light manipulation in photonic chips. Their exceptionally high nonlinearity and strong grating-induced dispersion near the stop-band edges significantly reduce the power and length required for chip-scale light–matter interactions. Using computational methods, we theoretically investigate modulational instability, Fermi–Pasta–Ulam

Nonclassical states of light are fundamental in various applications, spanning quantum computation to enhanced sensing. Fast free electrons, which emit light into photonic structures through the mechanism of spontaneous emission, represent a promising platform for generating diverse types of states. Indeed, the intrinsic connection between the input electron wave function and the output light field

Janus metasurfaces have emerged as a promising platform to enable independent wave manipulation by fully exploiting the inherent propagation direction of electromagnetic waves. These structures allow achieving distinct wavefront functionalities based on the direction of wave propagation. Concurrently, metagratings have gathered significant attention as an innovative design scheme for wavefront manipulation

In this opinion, we describe the potential of an emerging class of flat optics known as “nonlocal metasurfaces” to manipulate light in both real space and momentum space. While the ultimate form of a conventional “local” metasurface can be viewed as a universal generator of any desired waveform from a fixed input wavefront, the ultimate form of a nonlocal metasurface would instead act as a universal

Passive reflective metasurfaces can possess perfect absorption conditions: Singular scattering anomalies at which all impinging light is absorbed. Perfect absorption is a common yet powerful metasurface design option with applications in energy harvesting, sensing, and more. Less common is the inclusion of optical gain to the system, which can give rise to a singular condition for perfect amplification

Recent studies have demonstrated that a laser can self-generate frequency combs when tuned near an exceptional point (EP), where two cavity modes coalesce. These EP combs induce periodic modulation of the population inversion in the gain medium, and their repetition rate is independent of the laser cavity’s free spectral range. In this work, we perform a stability analysis that reveals two notable

In today’s rapidly evolving quantum landscape, the generation and manipulation of quantum light not only represent fundamental challenges but also herald unprecedented opportunities in communication, computing, sensing, and imaging. This special issue brings together a collection of contributions that span the entire journey, from the creation of quantum light using novel materials and emitters to

Finite-size effects occurring for quasi-bound states in the continuum (qBICs) formed in symmetric and asymmetric all-dielectric waveguide grating couplers are investigated using numerical simulations for different configuration parameters. We find that the beam size plays a crucial role in the formation of additional qBIC resonances originating in forbidden for plane-wave incidence BIC resonances,

Solid-state quantum emitters operating in the telecom wavelength range are pivotal for the development of scalable quantum information processing technologies. In this review, we provide a comprehensive overview of the state-of-the-art solid-state emitters of single photons targeting quantum information processing in the discrete-variable regime and telecom wavelength range. We focus on quantum dots

Polaritons are quantum mechanical superpositions of photon states with elementary excitations in molecules and solids. The light–matter admixture causes a characteristic frequency-momentum dispersion shared by all polaritons irrespective of the microscopic nature of material excitations that could entail charge, spin, lattice or orbital effects. Polaritons retain the strong nonlinearities of their

How topologies play a role in light–matter interaction is of great interest in control and transfer of topologically-protected structures. These topological structures such as skyrmions and merons have not yet been found in canonical momentum fields, which are fundamental in mechanical transfer between optical and matter fields. Here, we reveal the universality of generating skyrmionic structures in

The emergence of metasurfaces has enabled lightweight, compact imaging with degrees of freedom which previously required complex optical setups to achieve, such as polarization, wave vector, and spectrum. To date, most metasurface-enabled imaging systems have thus far been ‘passive’, and therefore subject to fundamental information and thickness limits set by the coupling of light to their sensor arrays

The development of on-chip optical frequency comb devices paves the way for novel applications in environmental tracking, fast ranging and smart communication solutions. Recently, a new type of frequency comb device, based on a modulated ring quantum cascade laser, was introduced and demonstrated. Here we present a rigorous theoretical study of this type of device, also known as the quantum walk comb

Nature can significantly inspire humans. Chameleons, jellyfish, and many other creatures use unique camouflage methods. Multispectral camouflage materials are highly desirable to against progressive multispectral detection. The proposed structure should be simple and highly transparent to ensure a wide application range. In this study, a bio-inspired multispectral camouflage material with visible transparency

Photonic bound states in the continuum (BICs) are optical modes that remain highly localized despite co-existing with radiating waves in the continuum, attracting considerable attention for both fundamental studies and technological innovations. Conventional single-mode BIC lasers predominantly focus on maximizing the Q-factor of a specific mode, often overlooking the critical role of Q-contrast –

The phenomenon of superoscillations is of great interest in microscopy, antenna design, and material sciences. This phenomenon has been generalized and has given rise to the concept of supershift, which is a far reaching extension that applies to functions that may present discontinuous derivatives. From this perspective, this is a notion that might have significant applications. This paper will provide

Silicon nitride (SiN) is a key material for quantum photonics due to its wide transparency window, high refractive index, low optical losses, and semiconductor foundry compatibility. We study the formation of single-photon emitters in SiN films grown by plasma-enhanced chemical vapor deposition (PECVD), exploring their photophysical properties and dependence on growth conditions. Emitters were observed

The nanoscale optical properties of high-quality MoS2 nanoribbons are investigated using THz nanoscopy based on a scattering-type scanning probe. The nanoribbons comprise a multilayer core, surrounded by monolayer edges. A featureless complex permittivity spectrum covering the range 0.6–1.6 THz is extracted from experimental time-domain measurements through a minimization procedure, adopting an extended

The confinement and manipulation of Janus particles have recently garnered significant interest due to their potential applications in fields such as nanotechnology and biophysics, where, under specific circumstances, they can act as microengines and drug carriers. However, the dynamics of Janus particles mostly rely on chemical reactions or thermal gradients, limiting their precision application.

Recent studies have shown that low-symmetry conductors under static electric bias offer a pathway to realize chiral gain, where the non-Hermitian optical response of the material is controlled by the spin angular momentum of the wave. In this work, we uncover the topological nature of chiral gain and demonstrate how a static electric bias induces topological bandgaps that support unidirectional edge

Dry synthesis is a highly versatile method for the fabrication of nanoporous metal films, since it enables easy and reproducible deposition of single or multi-layers of nanostructured materials that can find intriguing applications in plasmonics, photochemistry and photocatalysis, to name a few. Here, we extend the use of this methodology to the preparation of copper nano-islands that represent an

Nonlinear optical effects such as frequency conversion form the basis for many practical light sources. In a variety of settings, the performance of such sources is limited by quantum noise. In many nonlinear systems, this quantum noise gets strongly amplified, as a result of the large sensitivity of the nonlinear dynamics to changes in the initial conditions − a feature common to many nonlinear systems

We employ polarization tomography to characterize the modal properties of a dielectric nanocavity with sub-wavelength mode confinement. Our analysis of reflection spectra shows that the Fano-lineshape depends strongly on the polarization in a confocal configuration, and that the lineshape can be transformed into a Lorentzian-like peak for a certain polarization. For this polarization setting, the background

Optical trapping, also known as optical tweezing or optical levitation, is a technique that uses highly focused laser beams to manipulate micro- and nanoscopic particles. In optical traps driven by high-energy pulses, material non-linearity can result in unusual opto-mechanical effects, such as displaced equilibrium points. However, existing theoretical models of non-linear optical force on small particles

We demonstrate mid-infrared multiplexers based on evanescent couplers in In0.53Ga0.47As/InP ridge waveguides. Multiplexing of λ = 5.2 µm and λ = 8 µm input wavelengths in TM00 modes to a single TM00 output was achieved with 0.7 dB insertion loss. The demonstrated multiplexing bandwidth is significantly broader than is achievable using typical arrayed waveguide gratings, while displaying comparable

Metasurfaces have been widely exploited in imaging and sensing, holography, light–matter interaction, and optical communications in free space and on chip, thanks to their CMOS compatibility, versatility and compact form. However, as this technology matured from novelty to performance, stringent requirements on diffraction efficiency, scalability, and complex light control have also emerged. For instance

Polarization is a fundamental property of light that can be engineered and controlled efficiently with optical metasurfaces. Here, we employ chiral metasurfaces with monoclinic lattice geometry and achiral meta-atoms for resonant engineering of polarization states of light. We demonstrate, both theoretically and experimentally, that a monoclinic metasurface can convert linearly polarized light into

Terahertz vortex beams, carrying orbital angular momentum (OAM), are quite desirable for enhancing data transmission capability in telecommunication. However, it faces fundamental and technical challenges in a single metasurface to simultaneously generate orthogonal basis vortices with linear polarization (x- and y-polarity) and circular polarization (left- and right-handed polarity) under the orthogonal

Graphene hosts massless Dirac fermions owing to its linear electronic band structure. This distinctive feature underpins its extraordinary electronic properties, correlating to strong light–matter interactions on an extreme subwavelength scale. Over the past decade, intensive investigations have transitioned from fundamental graphene’s optical properties to practical application with the integration

Tailoring structured beams with varying lightwave properties along the longitudinal dimension has recently gained much interest. This paper gives a perspective on the advances of longitudinally structured beams, their potential applications, and future opportunities.

Plasmonic biosensors are powerful platforms for detecting various types of analytes. Specifically, surface-enhanced Raman spectroscopy (SERS) can enable label-free and selective detection. Shiga toxin-producing Escherichia coli (STEC) represents zoonotic pathogens that cause severe diseases, such as hemolytic uremic syndrome (HUS), the most important cause of acute renal failure in children. To date

A precise method for phase and amplitude detection in both the time and frequency domains of terahertz spectroscopy based on the weak-value amplification technique is proposed and demonstrated. Within the weak-value amplification scheme, the imaginary weak value enhances variations in the terahertz phase signals, whereas the real weak value amplifies changes in the terahertz amplitude signals. By employing

3D additive manufacturing enables the fabrication of nanophotonic structures with subwavelength features that control light across macroscopic scales. Gradient-based optimization offers an efficient approach to design these complex and non-intuitive structures. However, expanding this methodology from 2D to 3D introduces complexities, such as the need for structural integrity and connectivity. This

In this paper, we propose for the first time 100 GHz intelligent reflective surface (IRS) using screen-printable, high phase changing ratio vanadium dioxide (VO2). Sub-THz communications offer advantages such as ultra-high speed and ultra-low latency, it increases communication challenges due to path losses and non-line-of-sight (NLOS) problems. IRS is a representative solution to this NLOS problem

The metasurfaces are able to flexibly control electromagnetic waves. However, their design necessitates strict phase matching, which requires high computational load, and its control method has low flexibility. This paper proposes a novel method for the customization of the electric field of metalens with high degrees of freedom based on an improved Pixel Generative Adversarial Network (I-pixGAN).

An intermediate mirror has been proposed to enhance multijunction solar cell efficiency by selectively reflecting the light beyond higher energy bandgap of top cell, while simultaneously transmitting the rest of lower-energy light. Therefore, it reduces the higher-energy absorption spectral tail of the bottom cell (thermalization loss) and increase the absorption in the top cell. However, its effectiveness

Four-wave mixing is a widely used nonlinear process for wavelength conversion, parametric amplification and signal regeneration in various Kerr devices, which enables wavelength-tunability and lower-power operation in compact optical systems. Here, we demonstrate low-power continuous-wave four-wave mixing in an ultra-silicon-rich nitride topological waveguide leveraging the strong confinement of the

In this work, we extend temporal reflection and refraction analogies from the case of singlemode optical fibers to multimode fibers. Specifically, we show that nonlinear multimode fibers provide novel degrees of freedom that permit us to control optical pulse interactions. We take advantage of the properties of pulses propagating in different modes, such as their group velocities, dispersion parameters

Due to their attractive optical properties, 2D MXenes have garnered interest in nanophotonic and optoelectronic applications. However, tuning their properties typically requires the iterative synthesis of MXenes with a specific set of properties, such as the absorption band position, electronic conductivity, and dielectric constant. We demonstrate how to tailor the optical properties of MXene thin

We investigated the generation and control of fast photoelectrons (PEs) by exposing plasmonic nanoparticles (NPs) to short infrared (IR) laser pulses with peak intensities between 1012 and 3 × 1013 W/cm2. Our measured and numerically simulated PE momentum distributions demonstrate the extent to which PE yields and cutoff energies are controlled by the NP size, material, and laser peak intensity. For

The ability to train ever-larger neural networks brings artificial intelligence to the forefront of scientific and technical discoveries. However, their exponentially increasing size creates a proportionally greater demand for energy and computational hardware. Incorporating complex physical events in networks as fixed, efficient computation modules can address this demand by decreasing the complexity

Metasurfaces have attracted considerable interest in optical encryption due to their remarkable ability to manipulate light at subwavelength scales, however the aspect of encryption security remains an area requiring deeper exploration. Here, we propose and demonstrate metasurface-enabled optical encryption and steganography that provides dual-layer information protection. A secret information is embedded

Nonlinear dynamics provide an indispensable resource for creating quantum states of light, as well as other bosonic systems. Seminal work using second- and third-order nonlinear optical crystals, cavity quantum electrodynamics, and superconducting circuits, have enabled generating squeezed states, as well as various non-Gaussian quantum states (e.g., single photons, cat states) at both infrared and

Photonic integrated circuits (PICs) are transforming optical technology by miniaturizing complex photonic elements and systems onto single chips. However, scaling PICs to higher densities is constrained by optical crosstalk and device separation requirements, limiting both performance and size. Recent advancements in anisotropic metamaterials, particularly subwavelength gratings (SWGs), address these

The COVID-19 pandemic has profoundly impacted global economies and healthcare systems, revealing critical vulnerabilities in both. In response, our study introduces a sensitive and highly specific detection method for cDNA, leveraging Luminescence Resonance Energy Transfer (LRET) between upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs), and achieves a detection limit of 242 fM for

Solution-based optical gain materials offer a cost-effective path to coherent light sources. Further, bound states in the continuum (BICs) have garnered great interest owing to their diverging quality (Q) factors. Therefore, a hybrid of these – a solution-based material for optical gain and a BIC structure for the lasing mode – should constitute an ideal form factor for low-cost and low-threshold nanolasers

This article presents a control method for radial cell-pair rotations using a single-fiber manipulation technique that combines microcavity cascade optical tweezers with optical fiber mode coupling technology. It explores the mechanisms of cell manipulation under the influence of mode coupling and capillary fluid forces. By controlling the angle of fiber twisting and utilizing the birefringence effect

We look back at many challenges as well as unexpected successes encountered by the Mamyshev optical regenerator, which combines spectral broadening from self-phase modulation followed by offset bandpass filtering. Initially developed for ultra-fast all-optical processing of optical telecommunications signals, the Mamyshev regenerator has become most useful in the field of high-power fiber lasers. Implemented

The focused vortex beam generates a hollow beam, which has been widely used for size-controlled nanoparticle formation on various materials. However, the size variation of the vortex beam is limited by the integral order of the 2π phase wrap, while the waste is caused by the large side lobe around the center. In this study, we propose a method for hollow beam generation by splitting a femtosecond laser

In this paper, we model the interaction of a quantum emitter with a finite-size dispersive dielectric object in unbounded space within the framework of macroscopic quantum electrodynamics, using the modified Langevin noise formalism. The quantized electromagnetic field consists of two contributions: the medium-assisted field, which accounts for the electromagnetic field generated by the noise polarization

Human vital-sign sensing using electromagnetic wave has emerged as a promising technology for the noninvasive monitoring of individuals’ health status. Here, a modular reprogrammable metasurface system is presented to suppress noise in noninvasive human respiration sensing. The proposed reprogrammable Biological Metasurface (BioMeta) provides three-dimensional dynamic control over wavefront shaping

We synthesized crystalline films of neodymium nickel oxide (NdNiO3), a perovskite quantum material, switched the films from a metal phase (intrinsic) into an insulator phase (electron-doped) by field-driven lithium-ion intercalation, and characterized their structural and optical properties. Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) showed that the intercalation process resulted in