The information on the variations of indium composition, aggregation size, and quantum-well width is crucially important for understanding optical properties and, hence, fabricating efficient light-emitting devices. Our results showed that spinodal decomposition could occur in InGaN/GaN multiple quantum wells with content range 15%–25% (grown metal–organic chemical-vapor deposition). A lower nominal led to a better confinement indium-rich clusters within InGaN wells. interfaces became more...

The output enhancement of a green InGaN/GaN quantum-well (QW) light-emitting diode (LED) through the coupling QW with localized surface plasmons (LSPs), which are generated on Ag nanostructures top device, is demonstrated. suitable for generating LSPs resonance energies around LED wavelength formed by controlling deposition thickness and post-thermal-annealing condition. With 20 mA current injected onto LED, enhancements up to 150% in electroluminescence peak intensity 120% integrated...

An experimental investigation was carried out to study the effect of carbonation on mechanical properties and durability concrete. Ordinary portland concretes (OPC) with water/cement ratios 0.58 0.48 self-compacting (SCC) water/binder 0.40 0.36 were used in this study. Compressive strength test, splitting electrical resistivity rapid chloride penetration test (RCPT), open circuit potential method alternative current (AC) impedance performed estimate Test results showed that may compensate...

Efficient ultrafast all-optical switching in nonlinear directional couplers made of AlGaAs and AlGaAs/GaAs quantum wells near half the band gap is reported. The limited by multiphoton absorption which dominated three-photon this spectral range. well coupler stronger than that bulk AlGaAs. Autocorrelations output pulses bar cross states confirm pulse breakup through coupling, illustrate effects absorption. All sets experimental data are fitted a theoretical model.

The authors demonstrate the coupling effects between quantum well (QW) and surface plasmon (SP) generated nearby on p-type side in an InGaN∕GaN single-QW light-emitting diode (LED). QW-SP leads to enhancement of electroluminescence (EL) intensity LED sample designed for reduced SP energy leakage, when compared a weak or significant loss. In samples coupling, blueshifts photoluminescence EL emission spectra are observed, indicating one important features such process. device performance can...

A swept-source optical coherence tomography system is used to clinically scan oral precancer and cancer patients for statistically analyzing the effective indicators of diagnosis. Three are considered, including standard deviation (SD) an A-mode signal profile, exponential decay constant (alpha) A-mode-scan spatial-frequency spectrum, epithelium thickness (T) when boundary between lamina propria can still be identified. Generally, in abnormal mucosa, becomes larger, spectrum smaller,...

In this short paper, we present two methods: Quasi-images formula and finite-difference time-domain (FDTD) method to evaluate the electromagnetic fields very close lightning channel, which are applicable for poorly conducting ground case, numerical results consistent with each other. Moreover, vertical electric at 15 m obtained by proposed methods is in good agreement measured result, horizontal field a distance of 100 above finely FDTD identical accurate Cooray-Rubinstein approximation....

Flexible and transparent graphene films have been fabricated via chemical vapor deposition method, an extremely thin lightweight loudspeaker was obtained by transferring the on both side of polyvinylidene fluoride film. Once fed sound frequency electric field, graphene-based acoustic actuator could emit loud sounds in a wide range. Such film loudspeakers are transparent, flexible, magnet-free can be tailored into any shape size, which potential applications fabricating new type flexible devices.

An Ag protrusion array is fabricated on the p-GaN layer of an InGaN/GaN quantum-well (QW) light-emitting diode (LED) for generating surface plasmon coupling with radiating dipoles in QWs and hence LED emission enhancement. The tips protrusions penetrating into are close to such that induced near field around can strongly interact QWs. With protrusions, flip-chip shows a 74.6% enhancement output intensity at 100 mA injection current, when compared control sample no protrusion. simulation...

Nanoposts of 10–40 nm top diameter on an InGaN/GaN quantum well structure were fabricated using electron-beam lithography and inductively coupled plasma reactive ion etching. Significant blue shifts up to 130 meV in the photoluminescence (PL) spectrum observed. The blue-shift range increases with decreasing post diameter. For nanoposts significant strain relaxation, PL spectral peak position becomes less sensitive carrier screening. On basis temperature-dependent time-resolved measurements a...

Multiple-component decays of photoluminescence (PL) in InGaN/GaN quantum wells have been widely reported. However, their physical interpretations not well discussed yet. Based on wavelength-dependent and temperature-varying time-resolved PL measurements, the mechanism carrier transport among different levels localized states (spatially distributed) such an indium aggregated structure was proposed for interpreting early-stage fast decay, delayed slow rise, extended decay intensity. Three...

The simulation results of absorption enhancement in an amorphous-Si (a-Si) solar cell by depositing metal nanoparticles (NPs) on the device top and embedding NPs a layer above Al back-reflector are demonstrated. increase from near-field constructive interference electromagnetic waves forward direction such that increased amount sunlight energy is distributed a-Si layer. Among three used metals Al, Ag, Au, show most efficient enhancement. Between two NP geometries, nanocylinder (NC) more...

A swept-source optical coherence tomography (SS-OCT) system is used to clinically scan oral lesions in different carcinogenesis stages, including normal mucosa control, mild dysplasia (MiD), moderate (MoD), early-stage squamous cell carcinoma (ES-SCC), and well-developed SCC (WD-SCC), for diagnosis purpose. On the basis of analyses SS-OCT images, stages (MiD MoD), (ES-SCC WD-SCC) can be differentiated from control by evaluating depth-dependent standard deviation (SD) values lateral...

A procedure for computer analyzing an optical coherence tomography (OCT) image of normal and precancerous oral mucosae is demonstrated to reasonably plot the boundary between epithelium (EP) lamina propria (LP) layers, determine EP thickness, estimate range dysplastic cell distribution based on standard deviation (SD) mapping. In this study, 54 mucosa, 39 mild dysplasia, 44 moderate dysplasia OCT images are processed evaluating diagnosis statistics. Based SD mapping in image, it found that...

We demonstrate effective inactivation of oral cancer cells SAS through a combination photothermal therapy (PTT) and photodynamic (PDT) effects based on localized surface plasmon resonance (LSPR) around 1064 nm in wavelength Au nanoring (NRI) under femtosecond (fs) laser illumination. The PTT effect is caused by the LSPR-enhanced absorption NRI. PDT generated linking NRI with photosensitizer sulfonated aluminum phthalocyanines (AlPcS) for producing singlet oxygen two-photon (TPA) excitation...

The wavelength dependence of the nonlinear refractive index and two-photon absorption coefficient near half band gap was measured in an AlGaAs waveguide. two photon figure merit for efficient optics is shown to be quite favorable energies less than one gap.

Postgrowth thermal annealing of an InGaN/GaN quantum-well sample with a medium level nominal indium content (19%) was conducted. From the analyses high-resolution transmission electron microscopy and energy filter microscopy, it found that at 900 °C led to quasiregular quantum-dot-like structure. However, such structure destroyed when temperature raised 950 °C. Temperature-dependent photoluminescence (PL) measurements showed quite consistent results. Blueshift PL peak position narrowing...

Very few nonlinear optical materials are actually useful for high throughput all-optical devices. However, AlGaAs does satisfy all of the figures merit when used with photons energy less than one half semiconductor bandgap. Here we review our measurements pertinent coefficients in waveguides and various device applications to switching communications band around 1550 nm.

Reasoning systems that integrate explicit knowledge with implicit information are essential for high performance decision support in condition-based maintenance and prognostic health management applications. Such reasoning must be capable of learning the specific features each machine during its life cycle. In this paper, a hybrid approach is integrating domain test operational data from described. This illustrated an industrial gearbox example. expressed as rule-base used to train...

The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use novel optical systems and techniques for improved health care biomedical research.

We grew and processed a blue/green two-wavelength light-emitting diode (LED) based on the mixture of two kinds quantum wells (QW) in epitaxial growth. The X-ray diffraction photoluminescence measurements indicated that crystalline structure basic optical property individual QW are not significantly changed mixed relative electroluminescence (EL) intensity colors depends injection current level, which controls hole concentration distribution among QWs. At low levels, top green-emitting...

The dynamics of photoexcited excitons in thin $\mathrm{In}\mathrm{Ga}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ multiple quantum wells (QW's) with different In contents was studied by comparing the experimental data obtained photoluminescence (PL), PL excitation, and photoreflectance spectroscopy techniques results Monte Carlo simulations exciton hopping. temperature dependence linewidth demonstrated to be a fair agreement model phonon-assisted in-plane hopping within In-rich regions inhomogeneous...