Electrically injected GeSn lasers with peak wavelength up to 27 µm

2021 ◽  
Author(s):  
Yiyin Zhou ◽  
Solomon Ojo ◽  
CHEN-WEI WU ◽  
Yuanhao Miao ◽  
Huong Tran ◽  
...  
Keyword(s):  
Peak Wavelength

scholarly journals Electroless Deposited Gold Nanoparticles on Glass Plates as Sensors for Measuring the Dielectric Constant of Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Y. Kobayashi ◽  
Y. Ishii
Keyword(s):  
Dielectric Constant ◽  
Au Nanoparticles ◽  
Glass Plate ◽  
Au Nanoparticle ◽  
Peak Wavelength ◽  
Nanoparticle Deposition ◽  
Metal Plating ◽  
Large Dielectric Constant ◽  
Electroless Metal Plating ◽  
Glass Plates

This work describes a method for the deposition of Au nanoparticles on glass plates (Au-glass). An electroless metal plating technique was extended to the Au nanoparticle deposition. The technique consisted of three steps that took place on the glass plate: (1) adsorption of Sn2+ ions, (2) deposition of metallic Ag nuclei generated by reducing Ag+ ions with Sn2+ ions on the Sn-adsorbed sites, and (3) deposition of Au nanoparticles by reducing Au+ ions on the Ag surface. TEM observation revealed that metallic Au nanoparticles with a size of  nm were formed on the glass surface. A surface plasmon resonance absorption peak was observed, and its peak wavelength redshifted by immersing the Au-glass into a solution with a large dielectric constant. The redshift corresponded qualitatively to the calculation by the Mie theory accompanying the Drude expression, which was based on the change of the dielectric constant of the solution. The obtained results indicated that the Au-glass functioned as a sensor for measuring the dielectric constant of the solution.

Effects of V/III ratio of InGaN quantum well at high growth temperature for near ultraviolet light emitting diodes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohd Ann Amirul Zulffiqal Md Sahar ◽  
Zainuriah Hassan ◽  
Sha Shiong Ng ◽  
Way Foong Lim ◽  
Khai Shenn Lau ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Quantum Wells ◽  
Ultraviolet Light ◽  
Light Output ◽  
Emission Peak ◽  
Organic Chemical ◽  
Peak Wavelength ◽  
Content Type ◽  
Light Emitting ◽  
Near Ultraviolet

Purpose The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical properties of near-ultraviolet light-emitting diode (NUV-LED). Design/methodology/approach InGaN-based NUV-LED is successfully grown on the c-plane patterned sapphire substrate at atmospheric pressure using metal organic chemical vapor deposition. Findings The indium composition and thickness of InGaN QWs increased as the V/III ratio increased from 20871 to 11824, according to high-resolution X-ray diffraction. The V/III ratio was also found to have an important effect on the surface morphology of the InGaN QWs and thus the surface morphology of the subsequent layers. Apart from that, the electroluminescence measurement revealed that the V/III ratio had a major impact on the light output power (LOP) and the emission peak wavelength of the NUV-LED. The LOP increased by up to 53% at 100 mA, and the emission peak wavelength of the NUV-LED changed to a longer wavelength as the V/III ratio decreased from 20871 to 11824. Originality/value This study discovered a relation between the V/III ratio and the properties of QWs, which resulted in the LOP enhancement of the NUV-LED. High TMIn flow rates, which produced a low V/III ratio, contribute to the increased LOP of NUV-LED.

Design of Novel Sensitive Terahertz Biosensors Based on Graphene-Plasmonic Nanostructures

2021 ◽  
Author(s):  
Atefeh Chahkoutahi ◽  
Farzin Emami
Keyword(s):  
Structural Parameters ◽  
Absorption Peak ◽  
Plasmonic Nanostructures ◽  
Aluminum Layer ◽  
Absorption Factor ◽  
Peak Wavelength ◽  
Blood Samples ◽  
Chemical Potentials ◽  
Sensing Characteristics ◽  
Peak Value

Abstract In this paper, four different configurations of sensitive biosensors based on graphene-plasmonic combinations are designed and proposed. The nanostructures are made of graphene, SiO2, aluminum and gold layers on a silicon substrate. Graphene-ring shaped structures with diagonal strips in vertical and horizontal directions are considered in the structures which greatly affect the absorption characteristics (absorption peak value and wavelength). Aluminum layer is used in the structure to prevent the transmission of light throughout some layers and improving the absorption factor. To promote the functionality of the structures, effects of the structural parameters (R1 and R2) and chemical potentials (Ef1, Ef2, Ef3 and Ef4) on the absorption peak-wavelength and its value, are also studied. The four individual configurations with different layers and strip directions demonstrate distinct and different wavelength ranges; structure-1: 45-60 µm, structure-2: 50-70 µm, structure-3: 70-85 µm, and structure-4: 80-100 µm. Thus, they can be utilized for wide categories of applications. Sensitivities of 1500nm/RIU, 2250/RIU, 3750nm/RIU and 4850nm/RIU are obtained for four types, respectively. The proposed structures indicate more sensitivities and they can be used in acceptable sensing characteristics for different applications like hemoglobin and glucose concentrations in blood samples and can be utilized as refractive index bio-sensing sensors.

Emission Light Properties from Ag/Rhodamine-B LB Films Due to Surface Plasmon Excitations in the Kretschmann and Reverse Configurations

2000 ◽  
Vol 660 ◽  
Author(s):  
T. Nakano ◽  
H. Kobayashi ◽  
K. Shinbo ◽  
K. Kato ◽  
F. Kaneko ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Rhodamine B ◽  
Emission Angle ◽  
Attenuated Total Reflection ◽  
Peak Wavelength ◽  
Resonant Condition ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Kretschmann Configuration ◽  
Emission Light

ABSTRACTEmission light from Ag/ Rhodamine-B (RB) Langmuir-Blodgett (LB) films due to surface plasmon (SP) excitations has been investigated using the Kretschmann configuration of the attenuated total reflection (ATR) method and the reverse irradiation of laser beam from air to the samples. The conventional photoluminescence (PL) of the RB LB films showed a broad spectrum and the peak wavelength was about 600 nm. In the reverse irradiation, emission light was observed through the prism, and the intensities and the spectra strongly depended upon the emission angle where the light was observed. The wavelengths of the emission light became shorter as the emission angles increased. The relation between the wavelength and the emission angle agreed with the resonant condition of excitations of SPs in the Kretschmann configuration of ATR method. It was concluded that the emission light was caused by excitations of multiple SPs at the Ag/RB LB films.

Study the Effect of Junction Temperature on the Peak Wavelength in GaN-Based High-Power Green Light Emitting Diodes

2011 ◽  
Vol 399-401 ◽  
pp. 1034-1038
Author(s):  
Rong Rong Zhuang ◽  
Ping Cai ◽  
Jiang Li Huang
Keyword(s):  
High Power ◽  
Temperature Rise ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Red Shift ◽  
Junction Temperature ◽  
Spectral Peak ◽  
Peak Wavelength ◽  
Drive Current ◽  
Light Emitting

The junction temperature of GaN-based high-power green light emitting diodes is measured using the temperature coefficients of the diode forward voltage, from changes in temperature and changes in drive current to measure the LED junction temperature and the corresponding spectral, Respectively. Experiments show that, junction temperature due to environmental temperature increased, and the red shift of the spectral peak wavelength. When low temperature or less then the rated current range, the drive current increased in junction temperature rise due to the spectral peak wavelength blue shift . When the current is increased in the range of close to or greater than the rated current, leading to the junction temperature rise will cause spectral red shift . The peak wavelengths’ shift degree of 0.0579nm / k, 0.0751 nm / k and-0.1974nm / k, -0.0915 nm / k are calculated in both cases. The phenomenon is due to the LED junction temperature increases lead to band gap shrinkage, and the result of the role of spontaneous polarization and piezoelectric polarization in Ⅲ-nitride semiconductor materials.

Chromatic Confocal Displacement Measurment Based on Correlation Algorithm

2013 ◽  
Vol 446-447 ◽  
pp. 909-914
Author(s):  
Chun Hui Niu ◽  
Yong Lv
Keyword(s):  
Measurement System ◽  
Smoothing Spline ◽  
Peak Wavelength ◽  
Linear Fitting ◽  
Correlation Curve ◽  
Correlation Algorithm ◽  
Spline Fitting ◽  
Fitting Method ◽  
Spectrum Curve ◽  
Confocal Technique

Chromatic confocal technique application in displacement measurement is studied theoretically and experimentally. a set of refractive lenses are designed and a measurement system is established. Correlation fitting method is proposed to fit spectrum curve and find peak wavelength. Results with use of correlation fitting method are compared with Gaussian and smoothing spline fitting methods. It indicate that correlation fitting method have higher extracting accuracy of peak wavelength and smaller RMSE of linear fitting due to narrower and smoother correlation curve.

scholarly journals Random Fiber Grating Characterization Based on OFDR and Transfer Matrix Method

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6071
Author(s):  
Zichao Zhou ◽  
Chen Chen ◽  
Ping Lu ◽  
Stephen Mihailov ◽  
Liang Chen ◽  
...  
Keyword(s):  
Fiber Lasers ◽  
Spectral Response ◽  
Quantitative Relationship ◽  
Spatial Domain ◽  
Experimental Results ◽  
Period Variation ◽  
Peak Wavelength ◽  
Variation Range ◽  
Wavelength Variation ◽  
Simulation Results

Random fiber gratings (RFGs) have shown great potential applications in fiber sensing and random fiber lasers. However, a quantitative relationship between the degree of randomness of the RFG and its spectral response has never been analyzed. In this paper, two RFGs with different degrees of randomness are first characterized experimentally by optical frequency domain reflectometry (OFDR). Experimental results show that the high degree of randomness leads to low backscattering strength of the grating and strong strength fluctuations in the spatial domain. The local spectral response of the grating exhibits multiple peaks and a large peak wavelength variation range when its degree of randomness is high. The linewidth of its fine spectrum structures shows scaling behavior with the grating length. In order to find a quantitative relationship between the degree of randomness and spectrum property of RFG, entropy was introduced to describe the degree of randomness induced by period variation of the sub-grating. Simulation results showed that the average reflectivity of the RFG in dB scale decreased linearly with increased sub-grating entropy, when the measured wavelength range was smaller than the peak wavelength variation range of the sub-grating. The peak reflectivity of the RFG was determined by κ2LΔP (where κ is the coupling coefficient, L is the grating length, ΔP is period variation range of the sub-grating) rather than κL when ΔP is larger than 8 nm in the spatial domain. The experimental results agree well with the simulation results, which helps to optimize the RFG manufacturing processes for future applications in random fiber lasers and sensors.

scholarly journals Luminous and Melanopic Efficiency Performance of Phosphor-Converted LEDs with Tunable Spectral Characteristics

2020 ◽  
Vol 10 (18) ◽  
pp. 6198
Author(s):  
Peiyu Wu ◽  
Jiaqi Ju ◽  
Qi Yao
Keyword(s):  
Intensity Distribution ◽  
Emission Intensity ◽  
Spectral Characteristics ◽  
Spectral Composition ◽  
Light Sources ◽  
Peak Wavelength ◽  
Efficiency Performance ◽  
Circadian Effect ◽  
Color Rendering ◽  
Blue Intensity

In this work, we investigated the luminous and melanopic efficiency of the radiation (LER/MER) performances of phosphor-converted LEDs (PC LEDs) with tunable spectral characteristics, namely peak wavelength, full width at half maximum (FWHM), and emission intensity. We constructed theoretical PC LED spectra based on the characteristics extracted from the database of IES TM-30-15, analyzed the relations between LER/MER and different spectral characteristics, and proposed spectral composition strategies at various correlated color temperatures (CCTs). Results showed that both MER and LER are linear with the FWHM of phosphor within the peak wavelength range in practical use, but the change in values by tuning emission intensity varies with spectral compositions. Hence, different spectral characteristics should be considered comprehensively. We further explored the trade-off between luminous and melanopic efficiency. Lowering the FWHM of phosphor and the intensity distribution of the blue LED can obtain higher LER and low circadian effect at lower CCT. As CCT increases, considering color rendering and the increase in the blue intensity distribution, besides reducing FWHM, tuning the peak wavelength close to the peak wavelength of V(λ) helps to reduce the circadian effect. These investigations provide optimization strategies for ideal melanopic and luminous performance of PC LED light sources.

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