Optical Transmission Properties Research Articles

UV-vis spectroscopic studies of low-energy argon-ion-bombarded ion-exchanged glasses.

The ion-exchanged glasses bombarded with 80 eV, 100 eV, and 120 eV argon ions at room temperature are investigated. The optical and structural properties of ion-exchanged glasses before and after bombardment were analyzed by means of a UV-vis spectrometer, x-ray photoelectron spectroscopy, and electron probe micro analysis, respectively. The optical absorption and transmittance spectra of ion-exchanged glasses appear as obvious changes in the UV-visible region after bombardment. The optical absorption band and transmittance properties of ion-exchanged glasses at about 369-900 nm are less sensitive to the ion bombardment energy than that at about 200-280 nm. The changes in binding energy shift and peak area ratios of non-bridging oxygen and bridging oxygen contributions to the O 1s lines were observed with increasing ion beam bombardment energy. Accompanied with out-diffusion of potassium cations during argon ion bombardment, the peak of potassium cations concentration in the exchanged region decreases and moves into the interior of glasses in different degrees. The results show that variation of structure and optical properties of the ion-exchanged glasses are indicative of alterations of the silicate network structure induced by argon ion bombardment, which provide important information for application of the ion-exchanged glasses.

Investigation on dispersion parameters of Molybdenum Oxide thin films via Wemple–DiDomenico (WDD) single oscillator model

In this paper, the dispersion parameters of Molybdenum Oxide thin films viz: oscillator energy, dispersion energy, transition moments, static refractive index, oscillator strength, and oscillator wavelength are estimated via Wemple–DiDomenico (WDD) single oscillator model. The crystal structural, surface morphological, and optical transmission properties of Molybdenum Oxide thin films are also investigated so as to extract vital in-put parameters for WDD model. The X-ray Diffraction and Fourier Transform of Infrared analysis confirm that the film fabricated at substrate temperature ~ 300 °C under goes a successful dual phase transformation from amorphous to α- and β-MoO3 crystalline phase. Static refractive indices of the films are found to be vary from ~ 1.84 to 2.04 with the increase of substrate temperature during the thin film growth process via thermal evaporation technique. Moreover, the optical constants viz: film density, porosity, absorption coefficient, optical band gap, Urbach energy, steepness parameter, and strength of electron–phonon interaction are also studied as a function of substrate temperature. This is to establish a correlation between optical constants and dispersion parameters in the present paper.

Optical and mechanical properties of self-written polymer waveguide between single mode optical fibers using UV photocurable monomer system

Self-written polymer waveguides have been constructed between two single mode fibers by single photon polymerization. Norland Optical Adhesives (NOA) were used as photopolymerizable system. A droplet of the monomer was deposited between two aligned fibers, the liquid drop then cured by broadband laser driven xenon lamp to form a polymer channel between the cores of the aligned fibers. Optical transmission, mechanical, and nonlinear optical properties of the waveguide were investigated. Polymer waveguide with 100 µm long showed insertion loss about 1.25 dB at 1550 nm. Then, the polymer bridges were put under longitudinal and transverse mechanical stress. The optimum strain of 75% was achieved. Finally, optical nonlinearity of coefficient of 0.8 mm long polymer waveguide was calculated which is about 1300 W−1 km−1, this value is about 1000 times greater than that of silica fiber.

RETRACTED: Ketotifen loaded solid lipid nanoparticles laden contact lens to manage allergic conjunctivitis

Contact lenses are idea medical device to sustain the release of anti-allergic ocular drugs like ketotifen along with added advantage to act as a physical barrier against airborne antigens. However, the conventional soaking method using ketotifen-packaging solution showed low drug uptake, high burst release and short release duration along with reduction in the optical transmittance and swelling properties of the contact lens. In this paper, ketotifen loaded pegylated solid lipid nanoparticles (p-SNLs) laden contact lenses were fabricated to overcome the issues related to eye drop solution (frequent instillation) and contact lens. The SLNs and p-SLNs soaked contact lenses showed high drug uptake and did not changed the optical, swelling and oxygen permeability of the contact lenses. The in vitro release data of the soaked contact lenses (SM-K) showed low drug uptake and short release duration (48 h). The SLNs/p-SLNs soaked contact lenses showed improved drug uptake and sustain ketotifen release up to 72–96 h. The most promising results were shown by direct SLNs/p-SLNs laden contact lenses, which showed sustain release up to 168–192 h (with low burst release). The contact lens was safe in ocular irritation studies and showed high tear ketotifen-concentration (rabbit eye model) in comparison to the eye drop solution. The work demonstrated the promising potential of pegylated solid lipid nanoparticles to deliver ketotifen without compromising the critical contact lens properties to treat and manage various ocular allergic conditions.

Photonic crystal with tunable air layers based asymmetric transmission film for space solar power station

In this paper, high-contrast asymmetric transmission film based on periodic one-dimensional photonic crystal with tunable air layers is presented for the spherical concentrator of the orb-shape membrane energy gathering array based space solar power station concept. As the thicknesses of the air gaps in the photonic crystal structure are precisely controlled, the optical transmission properties of the photonic crystals structure dynamically vary, allowing transmission of propagation waves in the forward direction but reflection in the reverse direction. The geometric parameters of the proposed photonic crystal structure are optimized to obtain both high forward transmittance and reverse reflectance over a broad operating wavelength range from 400 nm to 1200 nm and wide angle of incidence from 0° to 60°. The numerical simulations demonstrate that the average forward transmittance, reverse reflectance and the total solar ray collection ratio of the optimal structure amount to 99.3%, 95.2% and 94.5%, respectively.

Design optimization of orbital angular momentum fibers using the gray wolf optimizer.

Optical data communication based on the orbital angular momentum (OAM) of light is a recently proposed method to enhance the transmission capacity of optical fibers. This requires a new type of optical fiber, the main part of the optical communication system, to be designed. Typically, these fibers have a ring-shaped refractive index profile. We aim to find an optimized cross section refractive index profile for an OAM fiber in which the number of supported OAM modes (channels), mode purity, and the effective refractive index separation of OAM modes to other fibers modes are maximized. However, the complexity of the relationship between structural parameters and optical transmission properties of these fibers has resulted in the lack of a comprehensive analytical method to design them. In this paper, we investigate the process of designing OAM fibers and propose a framework to design such fibers by using artificial intelligence optimizers. It is worth mentioning here that this problem is intrinsically a multiobjective optimization problem, and the actual solution for such problems is not unique and leads to a set of optimum solutions. Therefore, at the end of the optimization process, a wide range of optimal designs will be obtained in which a trade-off is established in each of the solutions. We solve this problem with the multiobjective gray wolf optimizer (GWO) and compare the results with that of the single-objective GWO. The framework can easily find many optimal designs that support more than 20 OAM modes. The obtained results show that the proposed method is comprehensive and can optimize the structure of any OAM fibers. No human involvement, simplicity, and being straightforward are the main advantages of the proposed framework.

MIM waveguide structure consisting of a semicircular resonant cavity coupled with a key-shaped resonant cavity.

We describe the optical transmission properties of a surface plasmon polariton waveguide structure consisting of a metal-insulator-metal (MIM) waveguide and a semicircular resonant cavity coupled with a key-shaped resonant cavity. Finite element algorithm simulated the optical response of a MIM waveguide structure. The influence of coupling length, geometrical size, and asymmetry of the key-shaped cavity and the radius of the semicircular resonant cavity on the Fano resonance line was investigated. Results demonstrate that variation of the key-shaped cavity asymmetry leads to the appearance of dual Fano resonances. When materials with different refractive index fill in the key-shaped cavity, the MIM waveguide structure achieves a sensitivity of 1261.67 nm/RIU. This performance allows the waveguide to be used for nanoscale biosensor applications such as measuring glucose concentrations. We simulated various spiked glucose concentrations by calculating the frequency shift as the second Fano resonance line moves towards longer wavelength. Glucose concentrations were calculated from variations of the Fano resonant wavelength. The waveguide structure proposed in this paper shows impressive practical prospects for many applications in the chemical sensing and biomedical fields.

Fabrication of highly transparent Er3+, Yb3+:Y2O3 ceramics with La2O3/ZrO2 as sintering additives and the near-infrared and upconversion luminescence properties

Abstract Highly transparent Er3+, Yb3+:Y2O3 ceramics were fabricated by pressureless vacuum sintering method using La2O3 and ZrO2 as compound sintering additives. The microstructure, optical transmittance, upconversion and near-infrared spectral properties of the ceramics were investigated by X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry and spectroscopic analysis methods. The sintered ceramics displayed a pure cubic Y2O3 phase structure and a nearly pore-free microstructure with homogeneous grain morphology and grain-size distribution. The highest transmittance of Er3+, Yb3+:Y2O3 ceramics sintered at 1800 °C for 14 h with 9 at% of La2O3 and 3 at% of ZrO2 as compound additives was more than 82% in the range of 380–3000 nm. Under 980 nm wavelength excitation, the ceramics exhibited intense blue, green and red upconversion emission, and broad-bandwidth near-infrared emission centered at 1536 nm, which gives it the potential to act as a high-performance solid-state 1.54 μm near-infrared and upconversion laser gain media.

Travoprost loaded microemulsion soaked contact lenses: Improved drug uptake, release kinetics and physical properties

Currently, travoprost is delivered by eye drop solution (glaucoma management), which shows very low bioavailability and patient non-compliance. Drug loaded contact lenses can be used to bypass the limitations of dosage by eye drops (low bioavailability and frequent instillation). However, the conventional soaking method (via drug-packaging solution) shows poor travoprost uptake and significantly affects the swelling and optical properties of the contact lenses. The current research investigated the effect of a stable microemulsion system on travoprost uptake and its effect on the physical properties of contact lenses along with drug-release kinetics. In comparison to the conventional soaking method (T-SM, travoprost-packaging solution), the travoprost loaded microemulsion soaked contact lenses (T-ME) showed improved drug uptake (loading) and physical properties of the contact lenses. The flux data (in vitro release) of T-ME contact lenses had a slower, 48–120 h, release profile, compared to T-SM contact lenses (36–48 h). The in vivo drug release data in the tear fluid (New Zealand rabbit's eye) showed high drug retention in comparison to eye drop solution. Thus, the study demonstrates the application of microemulsion system to improve the travoprost loading capacity in the contact lens along with improvement in the swelling and optical transmittance properties.

Measurement of optical fiber geometry parameters by gray distribution fitting with Gaussian function

The geometry parameters of optical fiber affect the optical transmission and mechanical properties, which are the important indexes to measure the quality of fiber. Near-field light distribution method is recommended in GB15972.20-2008 for the measurement of geometry parameters. In order to distinguish the boundary between fiber core and cladding, the method needs to illuminate the fiber. The end face of the fiber core is a bright spot with unclear edge, so the true edge of the core and cladding cannot be accurately judged. In this paper, the distribution of mode field in optical fiber is analyzed. Theoretically, the solution of electromagnetic vector of mode field satisfies Bessel function, but Gaussian function can also be used under approximate conditions. Therefore, Gaussian function is used to fit the distribution of the fiber core in this paper, and the real edge of the fiber core and cladding can be obtained from the Gaussian function after fitting. This method is a further improvement on the measurement method of GB15972.20-2008. The experimental results show that when the cutting effect of the fiber is not good or the imaging quality is poor, the Gaussian function method fitting with mode distribution can still ensure the repeatability of the measurement and the stability of the measured data.

Synthesis and Characterization of CNT Composites for Laser‐Generated Ultrasonic Waves

AbstractIn the last few years, extensive progress in ultrasonic wave generation by using multiwalled carbon nanotubes (MWCNTs) in combination with polydimethylsiloxane (PDMS), functional composites, has been achieved. Due to high optical absorption of MWCNTs as perfect absorbers for laser beams and the high thermal expansion coefficient of PDMS, a compact transducer for ultrasonic wave generation at higher frequency can be realized. This study reports a novel method to synthesize MWCNT–PDMS composites deposited on a glass substrate by spray coating, which is done in a short time of 2 h. The layers (0.9–32.2 µm) show low optical transmission properties of 13.9–0.0% at a wavelength of 1047 nm. Apart from using a 1% Triton‐X‐100 stock solution and then diluted to a 0.1% relatively nonhazardous solution, no toxic chemicals are used. The Triton‐X‐100 solution is not hazardous for lab handling and is a commonly used lab detergent for the treatment of biological cells. The achieved sound pressure level is 3.4 MPa with a frequency bandwidth of 9.7 MHz. These results show the potential for a fast and nontoxic production of laser‐generated ultrasonic transducers, which can be used well in the field of nondestructive material testing of layered materials or in medicine with an appropriate frequency range.

Ultra-High Negative Dispersion Based Single Mode Highly Nonlinear Bored Core Photonic Crystal Fiber (HNL-BCPCF): Design and Numerical Analysis

In this paper, two different models of highly nonlinear bored core photonic crystal fibers (HNL-BCPCF) are presented and compared for attaining an ultra-high negative dispersion coefficient and high nonlinearity. We achieved this dispersion by tailoring a defect into the solid core of the two proposed models and appropriately scaling down the diameter of the neighboring airholes of the core. To investigate the optical transmission properties in the fiber, simulations were carried out employing the finite element method (FEM) having a perfectly matched layer. The simulation results exhibited large negative dispersion coefficients of − 2218 ps/(nm-km) and − 2221 ps/(nm-km) for the two proposed models, respectively, when the wavelength had been tuned to 1550 nm and the corresponding nonlinear coefficients stand out to be 117.6 W−1 km−1 and 118.4 W−1 km−1. The fabrication process had been made much more feasible as the design consists of circular airholes. In our analysis, this geometry of photonic crystal fiber is noticeably more robust for its successful achievement of an ultra-high negative dispersion with high nonlinearity and facilitates optical back propagation applications and dispersion compensation for optical transmission systems.

Growth and characterization of organic nonlinear optical material: hemikis (piperazine) 4-hydroxybenzoic acid monohydrate single crystal

Hemikis (piperazine) 4-hydroxybenzoic acid monohydrate (P4HBA) was successfully synthesized, and single crystal was grown by slow evaporation solution growth technique. It crystallized in monoclinic system with centrosymmetric space group P21/c. The grown crystal was characterized by powder X-ray diffraction analysis. High-resolution X-ray diffraction rocking curve was recorded to assess the perfection of the grown crystal. UV–visible and photoluminescence studies were performed to explore its optical transmission and emission properties, respectively. Thermal stability and decomposition of P4HBA was illustrated through TG/DSC analysis. The laser-induced damage threshold measurements were performed by using Nd:YAG laser. Third-order nonlinear optical parameters of P4HBA crystal were estimated by Z-scan technique using He–Ne laser of wavelength 632.8 nm.

Effects of Mg content and thermal treatments on optoelectronic and bending properties of transparent conductive indium tin oxide/AgMg bi-layer film

Thin film metallic glass of various Ag–Mg composition layers deposited by co-sputtering was utilized as the metallic layer in the transparent conductive electrode of indium tin oxide (ITO)/AgMg (IAM). A series of IAM system has been established, the relation between optoelectronics property and compositional variation was revealed. The optical transmittance and electrical properties of the bi-layered structure before and after furnace or laser annealing were investigated. The relative change in the resistivity of IAM after cycling bending stress was also determined to ensure the robustness of the bi-layered structure. The IAM could show the optical transmittance of 76.4% at 550 nm and sheet resistivity of 21.6 Ω/□. Furnace annealing at 200 °C improved the figure of merit for all IAM films by 3~48. Upon furnace thermal treatment, ITO/10 nm Ag75Mg25 films reached the highest figure of merit of 1.24 × 10−2 Ω−1 with an optical transmittance of 83.0% and a sheet resistivity of 12.5 Ω/□. The relative change in resistivity (ΔR/Ro) of the as-deposited IAM, following fatigue testing (10,000 cycles) with a bending strain ε = 0.357%, equals 0.42, which was remarkably lower than that of a 30 nm ITO film (ΔR/Ro = 0.93) on a polyethylene terephthalate flexible substrate.

Hydrophobic Performance of Core/Shell Nanoarrays Modified by Stearic Acid

In this paper, we successfully prepare hydrophobic surface of ZnO/ZnS nanorods arrays modified by stearic acid. The morphology, microstructure, optical transmittance and self-cleaning property are examined by SEM, XRD, UV-vis and water contact angle measurements, respectively. The ZnO/ZnS core/shell nanoarrays shows a higher value of water contact angle in compare with that of pure ZnO nanorods arrays. After treatment by stearic acid, the resulting ZnO/ZnS nanostructure exhibits the best hydrophobicity with water droplets about 146.5 . The results show that the surface hydrophobicity of ZnO/ZnS nanoarrays can be improved by using stearic acid with low-surface-energy.

Thermally-evaporated C60/Ag/C60 multilayer electrodes for semi-transparent perovskite photovoltaics and thin film heaters

ABSTRACT We investigated the characteristics of thermally evaporated fullerene (C60)/Ag/C60 (CAC) multilayer films for use in semi-transparent perovskite solar cells (PSCs) and thin-film heaters (TFHs). The top and bottom C60 layers and Ag interlayer were prepared using multi-source thermal evaporation, and the thickness of the Ag interlayer was investigated in detail for its effects on the resistivity, optical transmittance, and mechanical properties of the CAC electrodes. We used a figure-of-merit analysis to obtain a CAC electrode with a smooth surface morphology that exhibited a sheet resistance of 5.63 Ohm/square and an optical transmittance of 66.13% at a 550 nm wavelength. We conducted mechanical deformation tests to confirm that the thermally evaporated multilayer CAC electrode has a high durability, even after 10,000 times of inner and outer bending, rolling, and twisting due to the flexibility of the amorphous C60 and Ag interlayer. We evaluated the feasibility of using CAC electrodes for semi-transparent PSCs and TFHs. The semi-transparent PSC with 1.08 cm2 active area prepared with a transparent multilayer CAC cathode showed a power conversion efficiency (PCE) of 5.1%. Furthermore, flexible TFHs (2.5 × 2.5 cm2) fabricated on a thermally evaporated CAC electrode show a high saturation temperature of 116.6 C, even at a low input voltage of 4.5 V, due to a very low sheet resistance. Based on the performance of the PSCs and TFHs, we conclude that the thermally evaporated multilayer CAC electrode is promising for use as a transparent conductive electrode (TCE) for semi-transparent PSCs and TFHs, with characteristics comparable to sputtered TCEs.

Novel Polyvinyl Pyrrolidone–Loaded Olopatadine HCl–Laden Doughnut Contact Lens to Treat Allergic Conjunctivitis

Olopatadine HCl is an antiallergic drug used for the management of allergic conjunctivitis. Currently, it is delivered via eye drop solution, which is highly inefficient due to low bioavailability. Silicone contact lenses can be used to sustain the release of ophthalmic drugs. However, the presence of drug alters the optical transmittance and physical properties of the contact lens. The objective was to design a novel polyvinyl pyrrolidone (PVP)-coated olopatadine-ethyl cellulose microparticles–laden doughnut contact lens to sustained ocular delivery with limited alteration to the optical and swelling properties of the contact lens. The doughnut was implanted within the periphery of the lens using modified casting technique. Olopatadine HCl was loaded by soaking (SM-OL), direct loading (DL-OL), and doughnut casting method (DNT-OL). PVP (comfort agent) was loaded on the surface of contact lens for all the batches via novel curing technique. The in vitro olopatadine HCl release data of SM-OL (up to 48-72 h) and DL-OL batches (up to 72 h) showed high burst release, whereas DNT-OL batch showed sustained release up to 120 h without significant (p > 0.05) alteration in the optical and swelling properties of contact lens. All the batches showed sustained release of PVP up to 120 h. The in vivo studies in the rabbit tear fluid showed improvement in the olopatadine HCl and PVP retention time in comparison to eye drop solution. The PVP-loaded DNT-OL-500 lens showed tear stabilization (comfort wear) in Schirmer strip test (rabbits) with no protein adherence in comparison to DNT-OL-500 lens without PVP. The study demonstrated the successful delivery of olopatadine HCl and PVP-K30 from the doughnut contact lens for the extended period with limited alteration to the optical and swelling properties of contact lens.

Structural, optical, thermal and nonlinear optical properties of Triphenylamine (TPA) single crystal grown by Bridgman – Stockbarger method

Optically transparent Triphenylamine (TPA) single crystal has been grown by Bridgman-Stockbarger method. Phase confirmation of TPA crystal was investigated using SXRD and PXRD analyses. Hirshfeld Surface was performed on TPA. The chemical bonding structure of TPA has been obtained from the FTIR spectral study. Optical transmittance properties of the grown crystal were obtained from the UV–Visible NIR spectrum analysis. Thermal properties of the TPA single crystal were identified using TG-DTA analyser. Q-switched Nd:YAG laser (λ = 1064 nm) has been used for the LDT measurement. Second harmonic generation of organic TPA crystal was analysed by Kurtz- Perry powder technique.

High-performance double-network ionogels enabled by electrostatic interaction.

Production of highly conductive and mechanically robust ionogels is urgently needed for the development of diverse flexible electrical devices, but it remains challenging. Herein, we report a facile strategy to prepare high-performance ionogels (ionic conductivity of 1.9 S m−1, fracture strain of 170%) via electrostatic interaction between mechanically robust charged gel double networks and conductive ionic liquids. Ionogels based on charged polymer networks (with electrostatic interaction) exhibit obvious higher optical transmittance, ionic conductivity, and better mechanical properties compared with those based on neutral polymer networks (without electrostatic interaction). Ionic conductivity and mechanical properties of the ionogels can also be regulated by the double-network structure of the gels. We further develop an ionic skin sensor with the high-performance ionogels used as ionic conductors, which can exhibit excellent sensing performance even under harsh conditions. We envision that this new class of high-performance ionogels would be an attractive alternative to traditional hydrogels, and would extend the applications of ionic conductors to extreme environments.

Preparation and properties of multi-effect potassium sodium niobate based transparent ferroelectric ceramics

Traditional transparent materials, including glasses and polymers, are chemically unstable and mechanically weak. Single crystals of some inorganic materials are also optically transparent, which are more stable than glasses and polymers. The fabrication of crystals, however, is relatively slow. Fortunately, transparent ceramics emerge as a promising candidate. Transparent ferroelectric ceramic is a kind of transparent ceramic with electro-optic effect, which also has excellent characteristics of conventional ceramics with excellent mechanical properties, resistance to high temperature, resistance against corrosion, and high hardness. Lead based transparent ferroelectric ceramic dominates this field for many years due to its superior electro-optic effect. Owing to the high toxicity of lead oxide, however, its development is significantly hampered. Therefore, it is greatly urgent to develop the lead-free transparent ferroelectric ceramics with excellent properties to replace the traditional lead based ceramics. In this paper, (K<sub>0.5</sub>Na<sub>0.5</sub>)<sub>0.94–3<i>x</i></sub>Li<sub>0.06</sub>La<i><sub>x</sub></i>Nb<sub>0.95</sub>Ta<sub>0.05</sub>O<sub>3</sub> (KNLTN-La<sub><i>x</i></sub>; <i>x</i> = 0, 0.01, 0.015, 0.02) lead-free transparent ferroelectric materials are fabricated by the conventional solid state reaction method and ordinary sintering process. The dependence of microstructure, phase structure, optical transmittance and electrical properties of the ceramic on composition are systemically investigated. The transparent ferroelectric ceramic with relaxor-behavior is obtained at <i>x</i> = 0.02. The optical transmittance of the ceramic near infrared region is as high as 60%. Meanwhile, the electrical properties of the ceramic at <i>x</i> = 0.01 still maintains a relatively high level (<i>d</i><sub>33</sub> = 110 pC/N, <i>k</i><sub>p</sub> = 0.267). In addition, the Curie temperature for each of all the samples is higher than 400 ℃. These results suggest that this material might be a novel and promising lead-free material that could be used in a large variety of electro-optical devices.