Since electroluminescent (EL) quantum dots (QDs) are considered a key component of the next-generation display, and large-scale production of environment-friendly QDs is required for their wide use in commercial displays. Therefore, several studies on non-cadmium QDs, such as indium phosphide (InP) QDs in the III-V category, graphene QDs, and copper indium sulfide (CuInS2) or silver indium sulfide

As an essential structure of infrared semiconductor lasers, the optical properties of InGaAsSb/AlGaAsSb multiple quantum wells need to be fully investigated. In this paper, the temperature and excitation power-dependent photoluminescence (PL) spectra of the InGaAsSb/AlGaAsSb MQWs are measured. A strong free exciton emission with a photon energy of 0.631 eV was observed at room temperature. Besides

An ultra-sensitive SERS (surface-enhanced Raman scattering) substrate was fabricated orderly by depositing 360 nm Ag film on the surface of V-shaped AAO (anodized aluminum oxide), utilizing NaOH solution to remove the AAO template, the neat volcano-like Ag arrays substrate (N-V-Ag) was obtained, and then depositing 1.5, 6 and 10 nm Ag film on the surface of the N-V-Ag to obtain the AgNPs decorated

A narrow linewidth (Δλ < 0.07 nm), low noise, widely tunable Er:Yb ring fiber laser is demonstrated using a fiber Bragg grating mirror embedded in a 3D printed polymer beam. By bending the polymer beam, continuous tuning of the laser was achieved over 30 nm, from 1543 nm to 1574 nm, with power variation below 1 dB, showing high temporal and spectral stability and a signal-to-background value exceeding

Chiroptical effects are instrumental for various intriguing applications like chiro-optical spectroscopy and chiral imaging. Their on-chip realization can open novel avenues for the demonstration of these applications at a miniaturized scale. One can leverage the unprecedented flexibility of metasurfaces to tailor the spinning light meticulously for realizing these chiroptical effects at a compact

Nanogap-rich silver nanoislands with fascinating optical properties are desirable substrates for surface-enhanced Raman scattering (SERS). Here, we propose a simple and high-throughput approach through the laser molecular beam epitaxy (LMBE) technique for preparing silver nanoislands containing large numbers of intra-nanogaps on a silicon wafer (6×6 cm2). By optimizing the deposition time, the enlarged

Ultrashort-pulse laser surface and bulk nano- and micromachining of dielectrics have multiple promising applications in micro-optics, microfluidics, and memory storage. The fundamental principles relate intrinsic inter-band multi-photon (MPA) and laser-induced intra-band free-carrier absorption (FCA) to particular ablation mechanisms and features. These principles are yet to be quantified into a complete

Yttrium fluoride (YF3) thin films with a thickness range of 10.8−1079.0 nm were prepared by electron beam evaporation. Spectroscopic ellipsometry was used to study the thickness-dependent optical properties of YF3 ultrathin films in the 300−820 nm wavelength range. With increasing thicknesses, the refractive indices of the intrinsic YF3 films increase slightly and approach that of bulk YF3 due to the

A series of zinc oxide nanorods (ZnO NRs) were grown by chemical bath deposition and their optical properties as a retarder for display devices were investigated. The effect of the precursors, growth time, and calcination time on the morphology and the optical properties was examined. The vertically-grown ZnO NRs layer represented positive c-plate property. We simulated the antireflection property

Wide bandgap II-VI semiconductors, lattice-matched to InP substrates, show promise for use in novel, visible wavelength photonic devices; however, release layers for substrate removal are still under development. An under-etch method is reported which uses an InP substrate as an effective release layer for the epitaxial lift-off of lattice-matched ZnCdMgSe membranes. An array of 100-µm-square membranes

Aiming at a highly bright emitter, hybridized thin films consisting of organic dye TDBC J-aggregates (JA) and titanium oxide (TO) nanoparticles (NPs) have been fabricated successfully. The fluorescence intensity and the corresponding fluorescence quantum yield multiplied ca. 10 times and ca. twice, respectively. TO NPs have a high refractive index, and have no absorption loss like metal NPs. On the

First-principles analyses are performed on the diamond europium vacancy (EuV) color center. Three different models indicate that the structure of the EuV color center contains a stable vacancy around the Eu atom. Energy band calculations show that the stable EuV color center has spin polarization and its spin-up energy level structure is highly suitable as a single-photon source. The zero-point transition

The first results of the liquid nitrogen cooling effect on the spectral properties of a phosphor-related bismuth active center (BAC-P) have been presented. It is found that the small-signal absorption bands of BACs are mildly affected at liquid nitrogen temperature (LNT, 77 K), while the unsaturable absorption level is lowered moderately. Meanwhile, noticeable shape changes of luminescence spectra

We report on the characterization and analysis of the spectroscopic properties of an Er3+-doped Ba(Zr,Mg,Ta)O3 (Er:BZMT) transparent ceramic showing a disordered perovskite structure. The Judd-Ofelt model was applied to estimate the radiative lifetimes and branching ratios of the 1.5 and 3 µm emission transitions, which are potential for laser operation. The experimental fluorescence lifetimes of the

A single and mixed-phases SnO2 (M-SnO2) nanostructures were synthesized by a simple spray pyrolysis method. The nanostructural crystallinity, surface morphology and optical evolution of Ba-doped tetragonal phase SnO2 with different Ba contents were studied by x-ray diffraction, atomic force microscopy, ultraviolet-visible spectroscopy and photoluminescence spectral measurements. The M-SnO2 with orthorhombic

We propose a four-layer WO3/Ag/PEI/CuSCN laminated transparent electrode with a PEI (polyethyleneimine) seed layer. The optical properties of the WO3/Ag/CuSCN electrode were simulated by a transfer matrix theory. Its optimal structure was WO3 (35 nm)/ Ag (9 nm)/CuSCN (47 nm), and the optical transmittance reached 92.7% at a wavelength of 550 nm. The transmittance decreased with the increase of the

Fiber-optical microendoscopy has made significant improvements to in vivo neural imaging, minimally invasive diagnostics, and microsurgery. However, high resolution, miniaturization, and low complexity cannot be simultaneously achieved together in the lens system for fiber-optical microendoscopy because current lens systems are in shape and dimensions restricted by limitations of manufacturing. Recently

A sub-picosecond mid-infrared laser based on hollow-core silica fiber is demonstrated for the first time. By using deuterium-filled revolver fiber as an active medium, we realized efficient two-cascade Raman conversion 1.03 → 1.49 → 2.68 µm pumped by chirped pulses of a femtosecond ytterbium laser. The gas fiber Raman laser generates ∼920 fs pulses at 2.68 µm with output pulse energy as high as 10

In this paper, a novel 2D ternary chalcogenide Ta2NiSe5 is fabricated into a saturable absorber by using the liquid phase exfoliation (LPE) method and successfully applied to the passive Q-switching experiment of Tm:YAP all-solid-state laser at 2 µm. The nonlinear optical absorption (NOA) properties of Ta2NiSe5 at 2 µm was measured by using an open-aperture Z-scan method, showing saturation fluence

We developed polymer-dispersed liquid crystals (PDLCs) that effectively scatter light both in the visible and near-infrared ranges simultaneously. Such PDLCs are characterized by an optimal size distribution of nematic liquid crystal droplets within 0.4 − 3 µm, which is achieved due to the specially selected copolymer, the elaborated liquid crystal material as well as the proper cooling mode from the

The effects of rapid thermal annealing (RTA) on aluminum nitride (AlN) waveguides were investigated. For the AlN prepared by the sputtering, high temperature annealing for too long time may deteriorate the device performance, while a 6-7 times RTA with a 60 s annealing at a temperature of 800 °C would result in a lowest waveguide loss of about 0.76 dB/cm. After annealing, self-pumped four-wave mixing

We present the design, fabrication and characterization of high quality factor silicon nitride nanobeam PhC cavities at visible wavelengths for coupling to diamond color centers in a cavity QED system. We demonstrate devices with a quality factor of ∼24, 000 (±250) around the zero-phonon line of the germanium-vacancy center in diamond. We also present an efficient fiber-to-waveguide coupling platform

Broadband absorption in the terahertz regime is a challenge and onerous to realize with a single layer metasurface. Self-similarity in fractal structures are exploiting metamaterial characteristics that offer a promising platform to design wideband microwave and optical devices. This paper presents a metamaterial absorber that consists of fractal geometry of Pythagorean-tree. The proposed metamaterial

The strong dispersion, ultra-thin form-factor and robustness to degradation make metasurfaces attractive for color filter applications. In particular, transmission-mode filters using silicon could potentially replace conventional color filter arrays in backside-illuminated CMOS image sensors and enable novel multispectral image sensors. We report a robust inverse-design methodology using polygon-shaped

In transparent conductive electrodes using silver nanowire (AgNW) networks, regions with and without AgNWs exhibit different optical properties. This phenomenon, known as “pattern visibility,” is typically undesirable. In this study, the intrinsic optical properties – absorption, scattering and extinction – of AgNW/polymer composite films are derived from transmission and reflection spectra measured

We experimentally determined the dispersion of third-order optical susceptibility χ(3) of graphene oxide (GO) in the visible region (450 - 750 nm) by combining spectroscopic ellipsometry and ultrafast pump and probe spectroscopy in the femtosecond regime. In order to mitigate the damage of wide-spectrum laser to photonic devices, GO has become a promising material for optical limiting (OL) devices

Manganese oxide nanosheets (MnO2 NSs) with two-dimensional formation and typically ultrathin thickness have gained a great deal of attention due to their excellent physical and chemical properties. However, the potential capability of MnO2 NSs in laser application has been rarely explored. Here, we first report the MnO2 NSs as the saturable absorber (SA) for generating Q-switched pulsed laser. The

In this work, we show controlled spatial and spectral modulation of local dielectric polarization in amorphous organic Alq3: DCM host: guest medium. We use self-strained silicon-dioxide microbeams to apply tensile strain on thin films at different DCM doping. From the measured spectral shift of the emission peak, we estimate the orientational polarizability (and in turn dielectric polarizability) in

We present theoretical investigations on designing a simple double nano-slit superlens for dramatically improving imaging quality for advanced plasmonic photolithography through introducing graphene as a plasmonic integrator. It is proposed that more than 235 times enhancement of localized electric field can be assured as the graphene layer is embedded in the designed superlens. It is observed that

We have proposed the use of surface plasmon resonances at the interface of hybrid magneto-photonic heterostructures [Opt. Mat. Express , 7, 4316 (2017)] for all-optical control of the macroscopic spin orientation in nanostructures in fs time scales. This requires strong spin-photon coupling for the resonant enhancement of opto-magnetic fields, generated through the inverse Faraday effect, in magnetic

The mechanism of a femtosecond laser-induced breakdown of deposited substrates mediated by aluminum nanoparticles in a vacuum environment was studied. This model of optical breakdown mediated by aluminum nanoparticles includes the electromagnetic field model for the description of near-field enhancement of aluminum nanoparticles, the two-temperature model for the description of electron and lattice

To detect mesoscale analytes with a size of hundreds of nanometers, we propose a three-dimensional gold nanobowl as a localized surface plasmon resonance (LSPR) sensor. Electromagnetic simulations demonstrated that the structural advantage obtained from the concave shape of the nanobowl enabled to extention of the local plasmon fields and consequently detected mesoscale analytes. Because the gold nanobowl

A structured SERS substrate with high uniformity and sensitivity was fabricated orderly by hydrophilizing the monocrystalline silicon substrate, self-assembling a layer of dense polystyrene (PS) microsphere array on the silicon, and depositing a layer (5 nm, 10 nm, 20 nm, 30 nm or 50 nm) of silver film. Rhodamine 6G (R6G) was used as a probe to characterize the performance of Raman enhancement. Experimental

Ho3+-doped low-hydroxyl (OH-) ZnF2 based fluoride glasses were prepared by using the conventional melt-quenching method in a glove box. The glasses have a composition of ZnF2-BaF2-SrF2-YF3-HoF3 (ZBSY-H), and the absorption coefficient of OH- in the ZBSY-H glasses was calculated to be only ∼0.003 cm−1 at 2.86 µm. Under the excitation of an 1120 nm laser, efficient 2.86 µm emissions were observed in

Major technological breakthroughs are often driven by advancements in materials research, and optics is no different. Over the last few years, near-zero-index (NZI) materials have triggered significant interest owing to their exceptional tunability of optical properties and enhanced light-matter interaction, leading to several demonstrations of compact, energy-efficient, and dynamic nanophotonic devices

Deterministic quantum dots (apex-QDs), which are spontaneously formed at the vertex of pyramid structures, are an attractive single-photon source. Herein, we propose the design of apex-QDs coupled to a single-mode optical fiber for directional emission from a quantum dot, followed by optimization of the structural parameters to maximize the extraction efficiency toward the fiber using FDTD simulation

Polycrystalline zinc selenide optical fibers and fiber lasers are expected to provide powerful capabilities for infrared waveguiding and laser technology. High pressure chemical vapor deposition, which is the only technique currently capable of producing zinc selenide optical fibers, leaves a geometric imperfection in the form of a central pore which is detrimental to mode quality. Chemical vapor transport

The spatial resolution of adaptive optics-optical coherence tomography (AO-OCT) enables visualization of retinal components (e.g., photoreceptors), which can advance clinical diagnosis of ocular diseases. Currently, however, variability in AO-OCT system performance suggests a need for standardized physical models, or “phantoms”, that replicate the opto-structural properties of retinal components. Here

Photonic waveguides are promising candidates for implementing parallel, ultra-fast and ultra-low latency interconnects. Such interconnects are an important technological asset for example for next generation optical routing, on and intra-chip optical communication, and for parallel photonic neural networks. We have recently demonstrated dense optical integration of multi-mode optical interconnects

Liquid crystal elastomers (LCEs) are highly suitable materials for the fabrication of flexible photonic elements due to their ability for directional actuation induced by external stimuli. 3D laser printing (3DLP) is a well-established method to realize complex photonic architectures. In this paper, we present the technological adaptations necessary to combine the actuation-controlled flexibility of

Er:GdScO3 crystal was grown by the edge-defined film-fed (EFG) method for the first time. The rocking curve showed that the as-grown crystal has a high crystalline quality. The peak absorption cross section at 980 nm is 0.38×10−20 cm2 with full width at half maximum (FWHM) of 19.5 nm and the peak emission cross section at 2720 nm is 0.93×10−20 cm2 with FWHM of 149.0 nm. The fluorescence lifetimes of

The GeS2-Ga2S3 vitreous matrix can incorporate metal halides in its network allowing the properties of the glasses to be adjusted following the composition. In this work, different systems containing either CsCl, CsI, CdCl2, or CdI2 are investigated in order to determine the compositions having the most suitable properties for drawing a step-index fibre. Indeed, transition glass temperatures and optical

Nanocomposites of LiZrO2 – LiBaZrO3: xMn2+ (x = 0–0.06 molar ratios) were prepared by the co-precipitation method. The prepared samples were characterized by X-ray diffraction (XRD), UV-visible spectrometry, photoluminescence (PL), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) techniques. Analysis of XRD data shows two phases: the cubic phase of BaZrO3 perovskite

Optical and thermo-optical studies of hydrogenated amorphous silicon-rich nitride films were carried out. The films were produced by plasma-assisted chemical vapor deposition on glass. It is shown that the films deposited under appropriately selected processing conditions contain little nitrogen, as confirmed by Fourier-transform infrared spectroscopy therefore they are referred to as silicon-rich

Ge5AsxTe95-x amorphous thin films (x=20∼60) have been deposited by thermal evaporation and the change of their optical parameters—like refractive index and optical bandgap as a function of thermal annealing time—have been studied with an aim to screen the composition of the film with stable optical and thermal properties for applications in optical waveguide devices. The film with a composition around

The Ge25Se75, Ge20Se80 and Ge15Se85 thin films were deposited in specular optical quality from n-propylamine - methanol solvent mixture by spin-coating technique. As-prepared solution processed thin films were thermally stabilized to reduce the content of organic solvent residuals and optical properties, surface topography, composition, structure and chemical resistance of prepared Ge-Se thin films

The performance of the electron-beam (e-beam) coatings can be easily affected by the environmental humidity due to their porous nature. We propose a shell layer strategy deposited by plasma ion-assisted deposition to cover the top surface and sidewall of the e-beam coating. The long-term optical and mechanical stability of the prepared multilayer coatings with and without the shell layer are compared

The potential of a Yb3+/Ho3+ co-doped lead-germanate glass as a laser gain medium around 2 µm is investigated by spectroscopic measurements and rate equation modelling. The glass, based on the molar composition of 56GeO2-31PbO-4Ga2O3-9Na2O and co-doped with 1.5 mol% Yb2O3 and 0.4 mol% Ho2O3, possesses a broad Ho3+ emission spectrum covering ∼1.8 µm to 2.2 µm for the Ho3+:5I7→5I8 transition, and a long

A high pulse energy Q-switched ytterbium-doped fiber laser (YDFL) based on copper oxide (CuO) nanoparticles as a saturable absorber (SA) is demonstrated. The CuO nanoparticles have been fabricated into a thin film using a liquid-phase exfoliation method then it was integrated into a laser cavity to act as Q-switcher. The proposed Q-switched YDFL operates at a central wavelength of 1035.4 nm with a

Transparent Dy:Y2O3 ceramics with various doping concentrations were fabricated by spark plasma sintering (SPS). Their optical characteristics, including emission cross-sections and nonlinear absorption properties, were evaluated. The results show that Dy:Y2O3 ceramics are promising as a new candidate for 3-μm laser gain medium and passive Q-switch material. A passive Q-switching of a 2795 nm Er:YAP

We used a negative-tone e-beam resist (N-ER) to perform direct laser writing lithography based on a single-photon absorption process with a 405-nm laser source. The linewidth of the N-ER reached 150 nm, which is over three times thinner than that of a conventional photoresist. To optimize the process, the linewidth, lithographic contrast, and aspect ratio of the N-ER were investigated with respect

Indium-doped zinc oxide (In:ZnO) nanocrystals are successfully produced by a simple refluxed sol-gel technique. The influence of post-heat treatment/ annealing temperatures on the structure, morphology, optical and luminescence properties of nanostructures was investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), energy

A method for direct growth of graphene nanowalls (GNWs) on an insulating substrate by plasma enhanced chemical vapor deposition (PECVD) is reported. The effects of growth temperature, plasma power, carbon source concentration, gas ratio and growth time on the quality of GNWs are systematically studied. The Raman spectrum shows that the obtained GNWs have a relatively high quality with a D to G peak

The objective of this work is to improve the optical properties of low refractive index polymers used for waveguide by introduction of inorganic nanoparticles. Copolymers of fluorinated monomers and glycidyl methacrylate are used. Introduction of SiO2 nanoparticles into polymer matrix is performed by direct mixing; copolymerization with SiO2 nanoparticles modified by monomer, and in situ sol-gel formation

Two-dimensional (2D) heterostructure materials have attracted increasing attention in ultrafast nonlinear optical applications due to their intriguing properties. Here, we fabricate a graphene/α-In2Se3 heterostructure by dropping α-In2Se3 dispersion onto the surface of few-layered graphene film and investigate its nonlinear optical responses. We show that the graphene/α-In2Se3 heterostructure has combined

We present a detailed exploration of the behavior of gallium phosphide (GaP) crystals used for optical rectification (OR) of high average power (> 100 W), MHz repetition rate ultrafast lasers. We measure thermal load, Terahertz (THz) refractive index and THz yield over a wide temperature range (77 K to 500 K) in this unusual excitation regime. Our thermal load measurements indicate that nonlinear absorption

In this study, the influence of the linear permittivity on the thermally-induced nonlinear optical properties of aluminum-doped zinc oxide thin films was investigated in the visible range, namely at 405, 532, and 650 nm. The strength of the nonlinear response in the films at these wavelengths represented by the thermal nonlinear index of refraction ($n_2^{th}$) and the absorption coefficients (β) magnitudes

In this work, a graphene hybrid plasmonic waveguide has been studied employing the finite element method. The graphene layers have been exploited here as optical absorber layers to extinguish the undesired plasmon modes in our system. Also, the silicon nanowires in our design, have been utilized to form a hybrid plasmon waveguide in order to achieve a high figure of merit of the desired plasmon mode

The kinetics of the electronic transitions within the f-shell of Dy3+ ions were studied with monitoring near- and mid-IR luminescence decay under pulsed laser excitation at 1.3 µm. The luminescence decay curves were found to be profoundly non-exponential in all bands in the range between 1.3-5.5 µm. Such behavior is attributed to cross-relaxation and up-conversion processes dominating in relaxation

21st-century studies in the field of epitaxy brought observable progress in a field of heterogeneous integration of III-V materials onto silicon photonic systems. BGaAs/GaP quantum wells (QWs) are a new material system, which can be grown on GaP/Si templates and thereby can be integrated with a Si platform. This work presents calculations of the material optical gain spectra for the QWs modified by