We present a new approach for producing elastomeric optical fibers with an optical behaviour corresponding to a few-mode optical fiber. Different fibers have been produced by first fabricating thermoplastic polyurethane preforms and subsequently drawing them. The fiber attenuation has been measured by the cut-back technique and the fiber bending transmission tolerance evaluated. The fiber potential

The bursts of picosecond laser pulses have nanosecond-level short interval delay. These bursts contain a variable number of sub-pulses, which are used for laser cutting of copper current collector and graphite anode material for Li-ion battery anode. The influences of 2–10 sub-pulses on kerf edges were studied and were compared with that of a single pulse. The shapes of anode edge cut under different

Terahertz (THz) metamaterials are widely used in biosensor devices due to their unique superiority, and the demand for new high sensitivity biosensors based on THz metamaterials is increasing. This paper presents a polarization-insensitive terahertz metamaterial sensor used for BSA detection. Simulation reveals that the peak of transmission spectrum shifts obviously when the sensor is covered with

We present the enhancement of the hot-electron emissions by the enhanced electric field with deep UV surface plasmon resonance (DUV-SPR). An aluminum disk–hole array was designed using the finite-difference time-domain (FDTD) method for enhancing the electric field by the disk–hole cavity coupling. We found that the photoelectron emission efficiencies were experimentally improved by four times and

Annealing treatments are an effective strategy to modulate trap depth and trap concentration in electronic materials. Herein, we have found that annealing in a weak reducing atmosphere is a good way to tailor the trap depth and trap concentration of the (LuYGd)(Al4Ga)O12:Ce3+,V3+ multicomponent phosphor. The characterization results show that the annealing atmosphere has no effect on the crystal structure

An easy and fast fabrication strategy to obtain Photochromic Films (PFs) for naked-eye detection of oxygen is presented. These PFs are based on the photoreductive activity of TiO2 nanoparticles combined with the redox-driven color switching property of methylene blue, embedded in a photocurable and tunable air-permeable polyethylene glycol diacrylate (PEGDA) matrix. The PF is fabricated by a single-step

We analyze the electromagnetic field near a plane interface between a conductive and a dielectric media, under conditions supporting surface plasmon-polariton (SPP) propagation. The conductive medium is described by the hydrodynamic electron-gas model that enables a consistent analysis of the field-induced variations of the electron density and velocity at the interface and its nearest vicinity. The

Gap plasmon structures could enable future ultrafast communication by allowing simultaneous nanoscale integration of electromagnetic waves, nonlinear and optical-electrical conversion, and providing a critical element often overlooked in this context: electrical contacts. Here, the fundamental limit of these structures is discussed, and it is argued that the conventional concept of “smaller is better"

High-rate direct femtosecond (fs) laser writing is a well-established technology for fabricating various micro-optical elements in bulk dielectrics. In this technology, the “heat accumulation” effect, occurring during high-repetition rate (∼ 1 MHz) exposure in dielectrics by a fs laser, enables ultralow-energy micro-modification via cumulative heating. Meanwhile, in this work in the transient multi-photon

In this paper, we introduced a switchable dual-band and ultra-wideband terahertz wave absorber based on photoconductive silicon combining with vanadium dioxide (VO2). In the terahertz absorber, photoconductive silicon cross array, silicon dioxide layer, vanadium dioxide windmill type array, silicon dioxide dielectric layer, and gold ground plane are placed from the top layer to bottom layer in sequence

In this work, an ultra-wideband microwave metasurface absorber with optically transparent and flexible properties is proposed. The metasurface is composed of a reflective backplane and a microwave absorption layer sandwiched between two dielectric substrates. The impedance matching curves of the microwave absorption layer are deduced based on the impedance matching theory, which is quite helpful and

Antimony sulfide (Sb2S3) nanobars are synthesized by the solvothermal method using different concentrations of the antimony chloride salt (SbCl3)at 180 °C for 14 h. The effects of 0.75, 0.8, 0.85, and 0.9 mmol of SbCl3 on the compositions, morphologies, and phases of the product are investigated. Raman spectroscopy indicates that the product corresponds to the pure orthorhombic phase of Sb2S3. Transmission

We correct three labeling errors, one in Fig. 4(a), and the other two in Section 3.2 of the manuscript text [Opt. Mater. Express 9, 826 (2019) [CrossRef] ].

This paper presents the inverse design of resonant nanostructures for extraordinary optical transmission of periodic metallic slits, where the topology optimization approach is utilized to implement the inverse design procedure and find the geometrical configurations of the nanostructures. By using the inverse design method, the subwavelength-sized resonant nanostructures, localized at the inlet and

A deep learning (DL)-based approach has been proposed to accurately model the relationship between design parameters and the Q factor of photonic crystal (PC) nanocavities. A convolutional neural network (CNN), which consists of two convolutional layers and three fully-connected layers is trained on a large-scale dataset consisting of 12,500 nanocavities. The experimental results show that the CNN

We propose a dual-band terahertz metamaterial sensor (MS), which exhibits the low loss and high quality (Q) factor of electromagnetically induced transparency (EIT) effects at the frequencies of 0.89 THz and 1.56 THz simultaneously. The physical natures of EIT effects are analyzed by using numerical simulations and a “two particle” model. Further, THz sensing is performed based on the shifts of two

Transparent quantum-dot light-emitting diodes (Tr-QLEDs) with an inverted architecture has been developed. The inverted Tr-QLEDs are designed for integrating with thin-film transistors (TFTs) circuit easily. The 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HAT-CN) is employed as a hole injection layer (HIL) as well as a buffer layer in the inverted Tr-QLEDs. An optimized HAT-CN as dual-functional

We realize and investigate a nonlinear metasurface taking advantage of intersubband transitions in ultranarrow GaN/AlN multi-quantum well heterostructures. Owing to huge band offsets, the structures offer resonant transitions in the telecom window around 1.55 µm. These heterostructures are functionalized with an array of plasmonic antennas featuring cross-polarized resonances at these near-infrared

We report a method to dynamically control the surface of gallium-based liquid metal to switch between reflective/diffusive states by removing/depositing oxide films via electrochemical redox reactions. Electrochemical oxidation deposits rough surface oxides that are optically diffusive. Electrochemical reduction returns the metal to a pristine, smooth, and reflective state. This switching is achieved

We develop a recurrent neural network framework to model the non-Markovian dynamics exhibited by two-level atoms interacting with the radiation reservoir of a photonic crystal. Despite the strong non-Markovianity of the atomic dynamics induced by the rapid spectral variation in photonic density of states of the photonic reservoir, our recurrent neural network approach is able to capture precise details

Silica optical fibers are employed in endoscopy and related minimally invasive medical methods thanks to their good transparency and flexibility. Although silicon oxide is a biocompatible material, its use involves a serious health risk due to its fragility and the fact that potential fiber fragments can freely move inside the body without the possibility of being detected by conventional methods such

Millimeter-wave (MMW) radiometry has been used in a vast and growing assortment of applications. Several MMW discriminators have been proposed and achieved good results in material classification and recognition. However, these discriminators are difficult to measure accurately in the real world. In this article, we defined two discriminators, emissive degree of polarization (EDoP) and reflecting DoP

Combining self-assembly technology and the thin-film annealing method, annealed Ag nano-islands (Ag NIs) with SiO2 microsphere (MS) arrays were prepared as surface-enhanced Raman scattering (SERS) substrate in this paper. A “top-binding” model was established to analyze the effect of SiO2 MS at different annealing temperatures and different Ag film thickness. The corresponding comparative analysis

In this paper, α-Ga2O3 nanorod arrays (NRAs) with preferential growth along the (110) direction were successfully prepared on the FTO substrate by the water bath method. With the help of a scanning electron microscope (SEM), X-ray diffractometer (XRD), and Raman spectrometer (Raman), the crystal structure and morphology characteristics of α-Ga2O3 NRAs were studied. On this basis, a photoelectrochemical

In this work, a thin-film MoS2/WS2/MoS2/WS2 heterostructure is employed as a saturable absorber (SA) material for efficient ultrafast pulsed laser operation, achieving a 17.54 GHz Q-switched mode-locked Nd:GGG waveguide laser fabricated by femtosecond laser direct-writing (FsLDW). The mode-locked pulse duration is measured to be as short as 31 ps. The maximum laser slope efficiency and the average

D-shaped fibers have attracted widespread attention due to their special structure and excellent performances. However, the fabrication of D-shaped fiber faces many challenges. Mechanical polishing and chemical etching are two traditional methods for D-shaped fiber fabrication, in which micro-crack or contamination is unavoidable. In this paper, we report an efficient method to produce D-shaped fiber

The electromagnetic response of plasmonic nanostructures is highly sensitive to their geometric parameters. In multi-dimensional parameter space, conventional full-wave simulation and numerical optimization can consume significant computation time and resources. It is also highly challenging to find the globally optimized result and perform inverse design for a highly nonlinear data structure. In this

In this paper, we report a study on Si nanopatterns, fabricated as a one-dimensional (1D) Si nanograting with a sub-wavelength (≈200 nm) period. Unpolarized light normally incident on the nanopatterned Si becomes partially polarized and chiral over the entire visible range of 380–740 nm. The degree and the state of polarization of light were measured using polarimetric and ellipsometric techniques

HfO2 has promising applications in semiconductors and optics due to its high dielectric constant and high refractive index. In this work, HfO2 thin films were deposited by plasma enhanced atomic layer deposition (PEALD) using tetrakis-dimethylamino hafnium (TDMAH) and oxygen plasma. The process optimization to obtain high quality HfO2 thin films with excellent uniformity over a 200 mm diameter is thoroughly

Research in the field of photonic integrated circuits (PICs) is taking a boost, especially because of its compatibility with the modern complementary metal-oxide semiconductor fabrication technology. Silicon-on-insulator slot waveguides are a burgeoning platform for sophisticated on-chip integration applications and have been extensively leveraged for PICs. Here the structural optimization and parametric

Achieving an ultra-narrow bandwidth analogue of electromagnetically induced transparency (EIT) in bright–bright mode coupling metasurface requires a large contrast of the Q factor and small wavelength detuning between the two coupled modes. Here, by coupling a toroidal dipole (TD) high-Q Fano resonance and a low-Q magnetic dipole (MD) mode, we numerically demonstrated a high Q factor analogue of EIT

Nanodiamonds containing silicon-vacancy (SiV) centers with high brightness, high photo-stability, and a narrow zero phonon line (ZPL) have attracted attention for bioimaging, nanoscale thermometry, and quantum technologies. One method to create such nanodiamonds is the milling of diamond films synthesized by chemical vapor deposition (CVD). However, this requires post-processing such as acid treatment

Surface enhanced Raman spectroscopy (SERS) with both enhanced activity and pronounced thermal stability is very suitable for ultra-sensitive monitoring of thermally assisted chemical bonding/fragmentation reactions in important industrial catalysis. Herein, we report an appealing thermally stable SERS active sensor based on the construction of multiple-branched Au/Ag nanodendrites (NDs). The obtained

In vivo tracking of harmonic nanoparticles (HNPs) in living animals is a technique not yet exploited, despite the great potential offered by these markers, due to a lack of an appropriate tool. The main drawback is the necessity to excite nonlinear effects in the millimeter area in a widefield mode with a sufficient signal to noise ratio. Our approach to this problem consists in a redesign of the laser

Errors have been found in subsection 3.2 (i.e., in page 1384) of our paper [Opt. Mater. Express 8, 1378 (2018) [CrossRef] ] as far as the identification of the grown layers within one period, for the quantum cascade laser structure shown in Figure 1(a). The correct text is as follows.

In this work, Er/Al/Ge co-doped silica glasses with different GeO2 content (0–3 mol%), as well as Ge/Al co-doped silica glasses, are prepared by combining the sol–gel and high-temperature sintering methods. Further, the effects of the GeO2 content on the absorptions and emissions properties, and lifetimes of the glasses before and after 1KGy γ-ray irradiation are compared. The Er/Al/Ge co-doped silica

We report on the feasibility of MXene and platinum diselenide (PtSe2) as novel saturable absorbers for the development of wavelength stabilized passively mode-locked mid-infrared fibre laser systems. After evaluating the performance of individual absorbers in a test cavity, we demonstrate a linear all-fibre laser cavity that utilizes a high reflective chirped fibre Bragg grating for wavelength selective

Hybrid fluorescent cholesteric liquid crystalline (CLC) materials are representatives of “smart” soft matter, and are characterized by light emission that can be flexibly controlled by various external stimuli. This fact is due to the many possibilities for potential applications in the fields of photonics and optics stimulating design, and study of this type of hybrid materials. Here, we report on

Machine learning has been widely adopted in various disciplines as they offer low-computational cost solutions to complex problems. Recently, deep learning-enabled methods for metasurface design have received increasing attention in the field of subwavelength electromagnetics. However, the previous metasurface design methods based on deep learning usually use huge datasets or complex networks to make

The inverse design of photonic devices through the training of artificial neural networks (ANNs) has been proven as an invaluable tool for researchers to uncover interesting structures and designs that produce optical devices with enhanced performance. Here, we demonstrate the inverse design of ultra-narrowband selective thermal emitters that operate in the wavelength regime of 2-8 µm using ANNs. By

The carrier dynamics and time-dependent photo-physical properties in the degradation period of hybrid organic-inorganic lead halide perovskites (HOIPs) are still unclear. Here a non-contact optical pump THz probe measurement was performed to observe the long-term degradation process of 2D passivated and cesium stabilized formamidinium lead iodide perovskite (FAPbI3) films. We find that photoconductivity

A very brief tribute to Mark I. Stockman and his contributions to optical science.

An introduction is provided to the feature issue of Optical Materials Express on Photonic Topological Materials.

Core/shell nanoparticles composed of a silica core over which a propargyl methacrylate (PMA) shell was polymerized around were synthesized. To employ the shell coating, the surface of the silica nanoparticles (SiNPs) was modified with an alkene-terminated organometallic silane linker that allowed for the covalent attachment of a poly(propargyl methacrylate) (pPMA) shell. The alkyne groups resulting

As the use of photonics circuits expands, the optical quality and performance of integrated components in the microscale become a major concern. Aiming to improve the performance while reducing the time processing, new microfabrication approaches are being investigated. The dewetting of glassy thin films have been recently proposed as an alternative for nano and microfabrication of chalcogenide optical

We report the direct generation of optical vortex arrays in a diode-pumped bulk Yb:CALGO laser. By adjusting the angles of the input mirror, output coupler and laser crystal to achieve off-axis-pumped condition, the ring-shaped LG0,±1, two to six order vortex array have been obtained. The phase singularities of optical vortex arrays were tunable from 1 to 6. When the pump power was 13.41 W, the maximum

Sapphire should be highly transparent for photon energies less than the band gap, but residual, weak absorption and scattering losses in the near infrared occur as a result of extrinsic and intrinsic defects. Lattice disorder, impurities, and point defects have all been implicated as being the origin of loss phenomena but very little experimental evidence exists to quantitatively establish the relationships

We experimentally demonstrated an all-fiber mode-locked erbium-doped laser based on Co2+:ZnSe (Cobalt, Zinc Selenide) thin film as the saturable absorber (SA), which was grown on the fiber taper by electron beam (e-beam) evaporation technology. The modulation depth, non-saturable loss and saturation intensity were found to be ∼12%, 76% and 1.89 MW/cm2, respectively. The X ray diffraction (XRD) results

The development of efficient dielectric coatings in the far UV (FUV) is demanded for upcoming space instrumentation, such as LUMOS (LUVOIR Ultraviolet Multi-Object Spectrograph) in LUVOIR mission, among other applications. Multilayers (MLs) based on MgF2 and LaF3 have been developed in the last decades for the 157-nm and 193-nm lithography, demonstrating excellent optical properties. Yet, the deposition

We fabricated an advanced transparent Yb-doped hexagonal fluorapatite ceramic with an average grain size of only 90 nm; we also demonstrated its laser oscillation. To the best of our knowledge, this is the smallest grain size for laser ceramics. The in-line transmittance was 86.1% at 1 µm for 0.79-mm-thick ceramics (corresponding to a loss coefficient of 0.45 cm-1). Although the ceramic crystal grains

To obtain high performance of GaN-based laser diodes (LDs), three series of LDs are proposed, the effects of Al content of p-AlGaN cladding layer, as well as the material composition and thickness of upper waveguide layer (UWG) are investigated separately. As the Al content increases, the threshold current and output power are found to improve significantly. Meanwhile, the optical field distributed

We report the light beam action on the nematic liquid crystal film with a free surface. It was found that a weak light absorption by the liquid crystal substrate dramatically changes the orienting properties of the light beam; in particular, a thermal gradient field induces an umbilical defect formation.

Two different types of azo dye-doped liquid crystal mixtures were separately nano-confined and characterized and then dispersed in the same host matrix to enhance the wavelength tunability of the laser-induced transparency of the fabricated polymeric thin film nanocomposites. The obtained results indicated that the transmitted intensity can be controlled separately by applying dual-wavelength pump

Developing strong electro-optic (EO) effect materials and devices is vital for high-speed optical communications and integrated photonics. In this work, we explored a chemical solution deposition technique to grow pure perovskite lead zirconate titanate (PZT) films on sapphire substrates. The grown PZT films demonstrated a preferential orientation and a broadband optical transmission window ranging

Both reduced graphene oxide (RGO) and gold (Au) nanoparticles have shown distinct nonlinear optical characteristics, such as saturable absorption, that are appropriate for generating ultrashort pulse lasers. Unfortunately, there are no studies of Q-switched waveguide lasers using RGO and RGO modified with Au nanoparticles (Au-RGO) as saturable absorbers. Here we perform the pump-probe experiments to

In this work, spark plasma sintering is used to mold non conventional chalcogenide glasses of high refractive index at low temperature (<400°C). This equipment, usually used for sintering refractory materials, is presented as efficient for both densification and high precision molding of IR transparent bulks and lenses of telluride glasses. Thermo-mechanical and optical characteristics of the selected

GaN-on-Si has become a useful fabrication route for many GaN devices and applications, but the mechanical stress incorporated throughout the material stack can impact the viability of this approach. The transfer printing of GaN membrane devices, a promising emerging technology, is most effective with flat membranes, but in practice many GaN structures released from their Si substrate are highly bowed

The compound eyes of natural insects endowed with the merits of a wide field of view (FOV), high sensitivity, and detection of moving targets, have aroused extensive concern. In this work, a large-scale artificial compound eye is fabricated by a high-efficiency and low-cost strategy that involves the combination of the thermal reflow method and pressure deformation. About 30,000 ommatidia are evenly

Rapid thermal consolidation of doped silica soot in a silicon carbide lined kiln subjected to microwave radiation is reported. The silica soot is fabricated through flame hydrolysis deposition and peak temperatures within the kiln reach >1350 °C after 18 minutes of irradiation. The glass underwent Newtonian cooling with an e−1 of approximately 5 minutes. Optical characteristics of the planar glass

Cyphochilus white beetle scales exhibit exceptionally strong light scattering power that originates from their regular random fibrillar network nanostructure. The structure is believed to be formed by late-stage spinodal decomposition in a lipid membrane system. However, the structure is characterized by nonconstant mean curvatures and appreciable anisotropy, which are not expected from late-stage