A comprehensive approach for simulating lasing dynamics in a liquid crystal based laser is presented. The approach takes into account the transformation of the liquid crystal structure caused by applied voltage. In particular, it allows us to explicitly account for a resonant mode frequency shift in the laser equations. The laser dynamic is described by a set of coupled non-linear differential equations for dye polarizations, population densities and the electromagnetic fields. The proposed model is applied to a photonic crystal-metal microcavity filled with a resonant nematic liquid crystal layer doped with a dye. The calculated lasing spectra governed by external electric field are verified in comparison with measured spectra.

Quantum light sources in van der Waals solid systems operating at room temperature have drawn significant attention, among which, with particular interest, is hexagonal boron nitride (hBN). Numerous efforts have focused on producing reliable, bright, and controllable single photon emitters (SPEs) in hBN. However, the identity of these emitters remains ambiguous, leading to unreproducible experimental results. Here, we offer direct evidence that hBN SPEs generated through annealing are not inside the hBN itself but originate from organic residues that carbonize and form aromatic fluorophores. Nanoscale Fourier transform infrared spectroscopy is used to analyze the emission sites, revealing the presence of carbon bonds in aromatic rings with a characteristic C═C absorption peak at 1650 cm-1. These emitters are primarily located in encapsulated areas of the hBN flake rather than uniformly distributed within the lattice. This finding opens the door to designing stable and reliable SPEs, enabling their integration into the rapidly growing quantum photonics applications.

Abstract The demand for noncontact temperature measurements is growing as the microelectronic features to be probed become progressively smaller. However, traditional thermal imaging with infrared cameras is fundamentally constrained by the micron-long wavelength of thermal emission. In this study, we explore a cost-effective, high-spatial-resolution thermography technique utilizing an uncooled silicon CMOS camera with an optical microscope setup. By detecting the integrated near-infrared (NIR, 700–1100 nm) thermal emission from Joule-heated metallic microstructures, our method successfully bypasses the traditional microbolometer’s diffraction limit and spatial resolution constraints. To ensure accurate temperature estimation, the camera is calibrated by leveraging the temperature-dependent Raman peak shift of hexagonal boron nitride flakes. Our optical microscope setup is in an oversampling condition, allowing us to exploit digital binning to achieve significant noise reduction and to directly visualize and map thermal emission at temperatures as low as 413 K for our titanium sample, which has an emissivity of around 0.4 in the NIR. This method provides a robust, highly capable tool for diagnosing localized thermal bottlenecks and mapping heat diffusion in high-density microelectronics.

Conventional ternary chalcogenide phase change materials (PCMs) have been widely used for near-infrared to mid-infrared applications but typically exhibit only two phases. In contrast, antimony sulfide (Sb2S3) is a binary phase-change material that can take three states and consists of earth-abundant elements. Despite its potential as a new class of PCM, Sb2S3 remains relatively underexplored. In the current work, we employ Raman spectroscopy and nano-FTIR to investigate phase transitions of Sb2S3 induced by femtosecond-pulsed and continuous-wave lasers. In particular, nano-FTIR enables nanoscale characterization of reversible phase transitions and clear identification of the typically elusive intermediate state. By integrating nano-FTIR and Raman spectroscopy, we correlate morphological and chemical features with optical responses. Crucially, the nano-FTIR amplitude distributions under broadband excitation are governed not only by the magnitude of the dielectric constant but also by the sensing depths. This work advances the understanding and application of binary chalcogenide PCMs for mid-infrared photonic devices.

Surface lattice resonance (SLR) lasers provide a promising platform for low-threshold, large-area coherent emission through collective coupling between localized surface plasmon resonances and lattice diffraction modes. However, low-threshold room-temperature operation remains fundamentally limited in plasmonic systems due to competing metallic absorption, radiative leakage, and lateral diffraction losses within the cavity. Compared with conventional dye-based gain media, the multiple quantum well (MQW) platform offers improved material stability and reproducibility. Here we demonstrate room-temperature SLR lasing at 930 nm by integrating a dielectric multiple-quantum-well gain medium with periodic metallic nanoparticle arrays. Rather than relying solely on Q-factor analysis, we establish that modal selection and threshold behavior are governed by geometry-dependent redistribution of dissipation channels. By systematically varying the metal filling factor, lattice constant, and nanoparticle geometry including circular, square, and rectangular shapes, we reveal that different lattice symmetries modify lateral coupling coefficients and lift modal degeneracy, thereby reshaping the balance among metallic absorption, radiative feedback, and lateral leakage. Among the investigated configurations, the square geometry with a filling factor of 10% achieves the lowest threshold of 0.059 MW/cm² and a linewidth of 1 nm. Our results demonstrate that gain-loss engineering through κ-mediated lateral coupling control provides an effective strategy to regulate modal dissociation and minimize effective cavity loss in plasmonic SLR lasers.

As on-chip integration advances, nanoscale light sources become critical, necessitating lasers that overcome the diffraction limit. Plasmonic nanowire lasers, leveraging surface plasmon polaritons at metal-semiconductor interfaces, enable ultracompact mode confinement. While recent efforts have enhanced their performance through structural design and two-dimensional materials, the complex multimode dynamics in nanowire cavities remain insufficiently understood. Here, we present a systematic approach to identify dominant transverse and longitudinal modes in InP nanowire lasers, offering insights into internal mode distributions. Building upon our previous demonstration of graphene-assisted threshold reduction and mode volume confinement in near UV nanowire lasers, we extend this strategy to the near-infrared regime. This work provides a deeper understanding of lasing behavior in nanowire systems, contributing to the design of integrated photonic components for high-density optical interconnects.

ABSTRACT A quasi‐bound state in the continuum (quasi‐BIC), which maintains a high Q ‐factor and localization of the electromagnetic field, is implemented in a dielectric metasurface. A liquid crystal (LC) layer covering the metasurface breaks the mirror symmetry and introduces chirality, leading to a chiral quasi‐bound state in the continuum (chiral‐BIC). Using the controllability of the LC, a change in circular dichroism (CD) through heating is demonstrated. Additionally, doping the LC with dye molecules enables a low‐threshold laser that emits elliptically polarized, temperature‐tunable radiation.

Diffraction orders at the Pancharatnam–Berry metasurface are efficiently switched by applying voltage. A liquid crystal layer introduced acts as a half-wave phase plate to exchange left- and right-circular polarizations of light. Applied voltage turns the polarization exchange on and off, causing redistribution of the intensity between the −1 and +1 diffraction orders. The proposed novel, to our knowledge, structure features a multilayer substrate that supports the Tamm plasmon polaritons, enabling the integration of both resonant and non-resonant phase-change mechanisms.

Phase-change materials (PCMs) provide a specific combination of properties. The binary semiconducting chalcogenide Sb2S3 is consider one of the promising candidates, especially its intrinsic high refractive index, low loss and wide bandgap properties, in near infrared (NIR). Here, the Sb2S3 transformation from amorphous to crystal state embedded between the distribute Bragg reflector (DBR) and metal layer. At the interface between DBR and metal layer in specific parameter, Phase-change Tamm plasmon–polariton (PC-TPP) resonance could be produce. The PC-TPP resonance has a 70 nm modulation wavelength. Also, the resonance achieves around 100 nm-shifted in NIR, depending on oblique angles.

Vanadium dioxide (VO 2 ), a representative phase‐transition material, exhibits nonlinear optical responses during its transition from an insulating to a metallic state. By investigating the transient photoresponses of a VO 2 thin film at different temperatures, additional slow‐growth and hybrid phases are discovered between the insulating phase at low‐temperature and metallic phase at high‐temperature. The amplitude of the VO 2 photoresponse at 68 °C in the slow‐growth phase is observed to be 5.5 times greater than that at room temperature. The controllability of relaxation time is also demonstrated from a few tens of picoseconds to a few nanoseconds. The optimized conditions for all‐optical modulation applications are explored.

Incorporation of phase-change materials (PCM) into nanophotonic structures is a straightforward method for making them tunable. The binary semiconducting chalcogenide antimony trisulfide (Sb2S3) is a suitable PCM for nanophotonic applications in the near-infrared (NIR) owing to its high refractive index, low optical losses, and wide bandgap. Therefore, in this study, Sb2S3 Tamm plasmon polaritons (TPPs) are fabricated with a focus on their widespread use in nanophotonic applications. For this, a gold film and Sb2S3 are deposited on the distributed Bragg reflector through e-beam evaporation. TPPs are excited at the interface between the distributed Bragg reflector (DBR) and the metal layer. The refractive index, extinction coefficient, and high-Q reflectance spectra of the developed Sb2S3 are measured and analyzed. The Sb2S3 TPPs exhibit a resonance shift of 45 nm caused by the phase change of Sb2S3 from amorphous to crystalline. In addition, the angle-dependent resonance shifts of 85, 76, and 63 nm are achieved by unpolarized, transverse magnetic (TM), and transverse electric (TE) modes near NIR light, respectively. The developed Sb2S3 TPP can be applied in various nanophotonics applications, including optical memory, optical data storage, and LiDAR receiver systems.

Vanadium dioxide (VO2), a representative phase-transition material, exhibits nonlinear optical responses during its transition from an insulating to a metallic state. By investigating the transient photoresponses of a VO2 thin film at different temperatures, additional slow-growth and hybrid phases are discovered between the insulating phase at low-temperature and metallic phase at high-temperature. The amplitude of the VO2 photoresponse at 68 degrees C in the slow-growth phase is observed to be 5.5 times greater than that at room temperature. The controllability of relaxation time is also demonstrated from a few tens of picoseconds to a few nanoseconds. The optimized conditions for all-optical modulation applications are explored.

Plasmonic nanocrystals represent one of the most fascinating emerging research fields and hold great promise for a wide range of new applications, including surface-enhanced Raman spectroscopy (SERS) and plasmon-related devices. Here, we present a mesocrystal consisting of 3D Ag nanocrystals (NCs) with the same orientation intercalated in a 2D muscovite crystal via a two-step hydrothermal process for a novel SERS platform. The fabricated Ag NCs/mica mesocrystal possesses high crystallinity, uniform size, and extensive distribution to benefit the SERS-active plasmon area and strong plasmon resonance in the visible spectral range. Furthermore, the SERS application potential was demonstrated through Raman spectra of crystal violet and rhodamine 6G molecules on a Ag NCs/mica mesocrystal with detection limits as low as 10-6 and 10-7 M. This work presents a 3D platform with large-scale uniform hot spots and cost-effectiveness for SERS applications, laying a solid foundation for further investigations into 3D plasmonic nanostructures.

Carrier dynamics in indium phosphide nanowires (InP NWs) was engineered through ionic liquid gating. A wavelength shift of 1.4 nm and repetitive switching between spontaneous and stimulated emission was demonstrated under minimal gate voltages.

Two-dimensional (2D) transition metal dichalcogenides are promising materials for next-generation photode-tectors. Therefore, controlling point chalcogen vacancies in chemical vapor deposition (CVD) synthesis is inevitable. In this work, the number of sulfur vacancies in monolayer WS2 flakes is well controlled in CVD synthesis, which resulted in a photoluminescence (PL) intensity difference. In addition, the relationship between the PL intensity and photoresponse of monolayer WS2 on graphene is discussed. The sulfur vacancies introduce defect trap states that cause carrier recombination and reduce carrier drift to graphene, thus decreasing the photocurrent. Furthermore, the gate-tunable Fermi level of graphene allows tunable responsivity of the WS2-graphene photodetector of up to 5 A/W with metal hard-mask fabrication. Our findings on the PL intensity and responsivity provide a simple and efficient strategy for choosing high-performance CVD-synthesized 2D TMD photodetectors.

The properties of circularly polarized light has recently been used to selectively reflect chiral metasurfaces. Here we report the more complete basic functionalities of reflectors and absorbers that display various optical phenomena under circularly polarized light at normal incidence as before. For the chiral metamirrors we designed, the circular dichroism in about 0.4 reflection is experimentally observed in visible wavelengths. The experimental results also show high reflectance for right-handed circular polarization with preserved handedness and strongly absorbed left-handed circular polarization at chiroptical resonant wavelengths. By combining a nanobrick and wire grating for our design, we find and offer a new structure to demonstrate the superposition concept of the phase in the same plane that is helpful in effectively designing chiral metamirrors, and could advance development of their ultracompact optical components.

In this study, we utilized a stress-sensitive superconductor MgB2 in combination with a flexible muscovite, a layered silicate, to demonstrate that materials in a reduced-dimension environment could be influenced by external strain. MgB2 nanocrystals were inserted into the muscovite interlayers using gas phase intercalation, creating a two-dimensional cavity-like structure. Several experiments confirmed that the cavity-induced static pressure from the intercalation effect and the external dynamic bending effect can affect the physical properties of MgB2. The results of analyzing the changes in superconducting critical temperature (T c) indicate that the dynamic bending effect corresponds to an applied pressure of approximately 1.2 GPa. This method demonstrates that muscovite intercalation serves as a versatile platform for evaluating the stress effects on functional materials in reduced dimensions under ambient conditions.

Nanoscale light sources are demanded vigorously due to rapid development in photonic integrated circuits (PICs). III-V semiconductor nanowire (NW) lasers have manifested themselves as indispensable components in this field, associated with their extremely compact footprint and ultra-high optical gain within the 1D cavity. In this study, the carrier concentrations of indium phosphide (InP) NWs are actively controlled to modify their emissive properties at room temperature. The InP NW lasers can achieve repetitive switching between photoluminescence (PL) and lasing with an extinction ratio of 22-fold by applying a gate voltage of 3 V using ionic liquid (IL) as a dielectric layer. IL brings forth ultra-high capacitance due to the nanometer-wide electric double layer (EDL) between interfaces, mapping out gating efficiency of ≈100-fold compared to the conventional bottom gate configurations. This IL-embedded nanolaser device can be a promising platform for the advanced integrated nanophotonic system.