Singular pole and enhanced sensitivity of PT-symmetric layered structure with resonators

2018 ◽  
Vol 84 (1) ◽  
pp. 10503 ◽  
Author(s):  
Rong-kun Ma ◽  
Jing Xia ◽  
Yun-tuan Fang
Keyword(s):  
Optical Properties ◽  
High Sensitivity ◽  
Refraction Index ◽  
Symmetric System ◽  
Scatter Matrix ◽  
Enhanced Sensitivity ◽  
Symmetric Structure ◽  
Single Cavity ◽  
Total Gain ◽  
Scatter Matrix Method

In order to achieve enhanced transmittance of parity-time (PT)-symmetric system, we design a layered PT-symmetric structure including resonators. We use the scatter matrix method to study the optical properties of the designed structure under the modulation of resonators. The structure system takes on a singular pole effect, i.e., the huge reflectance and transmittance occur at a special wavelength and period number. The field distribution reveals that the singular pole results from the coupling resonance of single cavity and the whole structure. Because of the coupling resonance, the total gain in layer A is much larger than the total loss in layer C. The reflectance and transmittance at the singular pole take on a high sensitivity on the refraction index of the resonators.

scholarly journals Effect of thickness on optical properties of pure Epoxy Resin plates

2014 ◽  
Vol 11 (2) ◽  
pp. 554-559
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Properties ◽  
Epoxy Resin ◽  
Energy Gap ◽  
Visible Region ◽  
Refraction Index ◽  
Ultraviolet Region ◽  
Intensity Increase ◽  
Absorption Intensity ◽  
Light Region ◽  
Different Thickness

In this study, Epoxy Resin plates was prepared by mixing epoxy(A) and hardner(B)with ratio(A:B) (3:1) with different thickness (0.3-0.96)cm. The effect of thickness on optical properties have been studied (absorption ,transmission ,reflectance) also the optical constant were found like (absorption coefficient, extenuation coefficient and refraction index) for all of the prepared plates. The results have shown that by increasing the thickness of plates., the absorption intensity increase in which at plates thickness (0.3-0.96)cm the absorption intensity were(1.54-1.43) respectively, and since absorption peak for epoxy occur in ultraviolet region and exactly at wavelength(368)nm and energy gap(Eg=3.05 eV) thus their good transmittance in the visible light region The plates have transmittance of about (60-83.4)% in visible region ,the refraction index for Elda epoxy is (n= 1.53 ) and its reflectance is (R=4 )% at wavelength (368 nm).

scholarly journals New Spectrofluorimetric Method with Enhanced Sensitivity for Determination of Paroxetine in Dosage Forms and Plasma

2008 ◽  
Vol 3 ◽  
pp. ACI.S1053 ◽  
Author(s):  
Ibrahim A. Darwish ◽  
Sawsan M. Amer ◽  
Heba H. Abdine ◽  
Lama I. Al-Rayes
Keyword(s):  
High Sensitivity ◽  
Dosage Forms ◽  
Official Method ◽  
Factors Affecting ◽  
Pharmaceutical Tablets ◽  
Enhanced Sensitivity ◽  
Spectrofluorimetric Method ◽  
Relative Standard ◽  
Optimized Conditions

New simple spectrofluorimetric method with enhanced sensitivity has been developed and validated for the determination of the antidepressant paroxetine (PXT) in its dosage forms and plasma. The method was based on nucleophilic substitution reaction of PXT with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in an alkaline medium (pH 8) to form a highly fluorescent derivative that was measured at 545 nm after excitation at 490 nm. The factors affecting the reaction was carefully studied and optimized. The kinetics of the reaction was investigated, and the reaction mechanism was presented. Under the optimized conditions, linear relationship with good correlation coefficient (0.9993) was found between the fluorescence intensity and PXT concentration in the range of 80-800 ng ml-1. The limits of detection and quantitation for the method were 25 and 77 ng ml-1, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 3%. The proposed method was successfully applied to the determination of PXT in its pharmaceutical tablets with good accuracy; the recovery values were 100.2 ± 1.61%. The results obtained by the proposed method were comparable with those obtained by the official method. The proposed method is superior to the previously reported spectrofluorimetric method for determination of PXT in terms of its higher sensitivity and wider linear range. The high sensitivity of the method allowed its successful application to the analysis of PXT in spiked human plasma. The proposed method is practical and valuable for its routine application in quality control and clinical laboratories for analysis of PXT.

Measurement of the Optical Properties of Muscle Tissue In Vivo

2000 ◽  
Author(s):  
P. L. Kopsombut ◽  
D. Willis ◽  
A. E. Schen ◽  
L. X. Xu ◽  
X. Xu
Keyword(s):  
Optical Properties ◽  
Transport Theory ◽  
Rapid Development ◽  
Ccd Camera ◽  
High Sensitivity ◽  
Biological Tissues ◽  
In Vivo Measurement ◽  
Living Tissues

Abstract Along with rapid development of diagnostic and therapeutic applications of lasers in medicine, optical properties of various biological tissues have been extensively studied [1]. Most of the studies were performed in vitro owing to the complexity involved in in vivo measurement. To date, it is well understood that living tissue is an absorbing and scattering heterogeneous medium because of its complex structures including blood network. The transport theory cannot be readily used due to the heterogeneity and the absence of the optical properties of living tissues [2]. In this research, we have developed a procedure for measuring the total attenuation coefficient (μ1) of the exteriorized rat 2-D spinotrapezius muscle in the wavelength ranged from 480–560 nm using the collimated light from a Nitrogen-pumped dye laser and a high-sensitivity CCD camera.

scholarly journals Infrared optical properties of aged porous GaAs

2001 ◽  
Vol 16 (5) ◽  
pp. 1241-1244 ◽  
Author(s):  
S. Zangooie ◽  
M. Schubert ◽  
T. E. Tiwald ◽  
J. A. Woollam
Keyword(s):  
Optical Properties ◽  
High Sensitivity ◽  
Vibration Modes ◽  
Angle Of Incidence ◽  
Long Wavelength ◽  
Volume Porosity ◽  
Aging Properties ◽  
Solid Part ◽  
Porous Gaas ◽  
Infrared Optical Properties

Aging properties of porous GaAs were investigated nondestructively using variable angle of incidence infrared spectroscopic ellipsometry. In addition to the thickness and volume porosity, properties of the solid part of the porous material are investigated in terms of the long-wavelength dielectric function and chemical composition. The high sensitivity is employed to detect and identify infrared resonant absorptions related to different vibration modes of cubic and amorphous As2O3. Resonances centered at 333.3, 480, 785.8, 838, and 1045.5 cm−1 are from cubic As2O3, whereas resonances centered at 350, 490, and 808.5 cm−1 are from amorphous As2O3.

scholarly journals Density Functional Study of Electronic and Optical Properties of Ternary Mixed Chalcogenides Topological Insulators

2016 ◽  
Vol 846 ◽  
pp. 599-606
Author(s):  
Alhassan Shuaibu ◽  
Md Mahmudur Rahman ◽  
Hishamuddin Zainuddin ◽  
Zainal Abdib Talib
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Topological Insulators ◽  
Local Density ◽  
Refraction Index ◽  
Functional Study ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Conductivity Function ◽  
Energy Dependent

This paper presented a theoretical study of structural, electronic, and optical properties of the ternary mixed chalcogenides Topological Insulators with a formula M2X2Y (M = Bi, X = Te and Y= Se, S) using density functional theory (DFT) within the local density approximation (LDA). From the calculation, we have evaluated the bulk modulus and its corresponding pressure derivatives of these compounds. The linear photon-energy dependent of dielectric functions, some optical properties such as reflectivity, refraction index, conductivity function, and energy-loss spectra, have also been obtained and analyzed within the electronic band structures and density of states of these compounds.

scholarly journals Effect of High Density Polyethylene (HDPE) on Structural and Optical Properties of (PP/PMMA) Blends

2015 ◽  
Vol 60 ◽  
pp. 94-106
Author(s):  
Majeed Ali Habeeb ◽  
Ahmed Hamza Abbas
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
High Density Polyethylene ◽  
Refraction Index ◽  
High Density ◽  
Band Gaps ◽  
Ir Spectrometry ◽  
Ft Ir ◽  
Pmma Blends ◽  
Dielectric Constant Increase

In the present work, Polypropylene (PP) was blended with poly methyl methacrylate (PMMA) to form (PP/PMMA) polymer blends. High Density Polyethylene (HDPE) was mixed into these blends at different weight fractions (2,4,6,8) % wt to form (PP/PMMA/HDPE) blends were prepared using an one screw extruder. results obtained from Scanning Electron Microscopy (SEM) revealed that there was a reduction in surface roughness any decrease in clusters, drilling and bends, as for Fourier Transform Infrared (FT-IR) spectrometry showed no change in the wave numbers of the functional groups. The optical properties of samples are investigated by measuring optical absorption spectra in the wavelength range from 260 to 1100 nm. this results show that Eg of the blends increases with increasing high density polyethylene contents, the indirect optical band gaps for (PP/PMMA) and (PP/PMMA/HDPE) blends were estimated to be about 2.83,2.9,2.95,3and 3.1 eV for indirect allowed transitions, whereas the indirect forbidden band gaps were determined as 2,2.1,2.15,2.2 and 2.3 eV with increase high density Polyethylene contents, respectively. The absorbance, absorption coefficient, extinction coefficient and the imaginary dielectric constant of (PP/PMMA/HDPE) decreases with increasing of HDPE percentages except the transmittance, refraction index and real part of the dielectric constant increase with increasing of high density polyethylene.

scholarly journals Enhanced Sensitivity and Detection of Near-Infrared Refractive Index Sensor with Plasmonic Multilayers

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7056
Author(s):  
Tan Tai Nguyen ◽  
Nguyen Van Sau ◽  
Quang Minh Ngo ◽  
Gauthier Eppe ◽  
Ngoc Quyen Tran ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
High Sensitivity ◽  
Dielectric Films ◽  
Silver Layer ◽  
Refractive Index Sensor ◽  
Detection Accuracy ◽  
Spr Sensor ◽  
Enhanced Sensitivity ◽  
Sensor Sensitivity

In this work, the multilayer of the surface plasmon resonance (SPR) sensor was optimized to achieve the maximum sensor sensitivity. By optimizing the thickness of the silver layer (Ag) and dielectric films (TiO2 and AlAs), the optimum sensitivity of the SPR sensor could be obtained. The performance of the SPR sensor proposed was compared with control simulations utilizing zinc oxide (ZnO) and molybdenum oxide (MoO3). The numerical results indicate that the figure-of-merits (FOM) of the SPR sensor was achieved around 150/RIU, corresponding to the sensor sensitivity of 162.79°/RIU with the optimized thicknesses of the TiO2, Ag, and AlAs layers of 140 nm, 60 nm, and 25 nm, respectively. This refractive index sensor shows the FOM to have high detection accuracy and high sensitivity that lead to finding potential application in bio-chemical detection with a small volume of liquid used in biological diagnosis.

scholarly journals Surface plasmon assisted toxic chemical NO<sub>2</sub> gas sensor by Au ∕ ZnO functional thin films

2021 ◽  
Vol 10 (2) ◽  
pp. 163-169
Author(s):  
Ravinder Gaur ◽  
Himanshu Mohan Padhy ◽  
Manikandan Elayaperumal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Surface Plasmon ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Film Material ◽  
Hybrid Thin Film ◽  
Spr Sensor

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.

Enhancing the Nonlinear Optical Properties of Lithium Tetraborate Glass Using Rare Earth Elements and Silver Nanoparticles

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050064
Author(s):  
M. A. Vallejo ◽  
S. Romero-Servin ◽  
Moisés I. Casillas Alvarez ◽  
Janet A. Elias Angel ◽  
C. Gomez-Solis ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Nonlinear Optical ◽  
Emission Spectra ◽  
Refraction Index ◽  
Lithium Tetraborate ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Matrix ◽  
Index Value

In recent years, nonlinear optics field is in constant growth, particularly on the characterization and study of optical properties of glass compounds. In this sense, the plasmonic effect caused by silver nanoparticles (SNP) on the nonlinear optical (NLO) properties of different materials was studied. Furthermore, we report the experimental absorption spectra, the emission spectra, Z-scan measurements in both closed and open apertures and scanning transmission electron microscopy (STEM) to show the morphology of the matrices and the nucleation of SNP. Moreover, some NLO parameters were calculated, such as the NL refraction index and NL coefficient absorption of lithium tetraborate (Li2B4O7) glass activated with rare earths (Dy3+ and Yb3+), as well as study of the effect of different concentrations of SNP. From the results obtained, it has been ascertained that the plasmon resonance caused by the presence of SNP enhances the NL refraction index value, as well as most of its linear optical properties in the matrix of Li2B4O7.

scholarly journals A Novel Sensor Prototype with Enhanced and Adaptive Sensitivity Based on Negative Stiffness Mechanism

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4644
Author(s):  
Lijun Liu ◽  
Yongzhong Nie ◽  
Ying Lei
Keyword(s):  
Low Frequency ◽  
High Sensitivity ◽  
Negative Stiffness ◽  
Micro Electro Mechanical Systems ◽  
Enhanced Sensitivity ◽  
Landslide Hazards ◽  
Negative Stiffness Mechanism ◽  
Low Sensitivity ◽  
Electric Filed ◽  
Design And Manufacture

Loess–mudstone/soil-rock interfacial landslide is one of the prominent landslide hazards that occurs in soil rock contacting zones. It is necessary to develop sensors with high sensitivity to weak and low frequency vibrations for the early warning of such interfacial landslides. In this paper, a novel monitoring sensor prototype with enhanced and adaptive sensitivity is developed for this purpose. The novelty of the sensitive sensor is based on the variable capacitances and negative stiffness mechanism due to the electric filed forces on the vibrating plate. Owing to the feedback control of adjustable electrostatic field by an embedded micro controller, the sensor has adaptive amplification characteristics with high sensitivity to weak and low frequency input and low sensitivity to high input. The design and manufacture of the proposed sensor prototype by Micro-Electro-Mechanical Systems (MEMS) with proper packaging are introduced. Post-signal processing is also presented. Some preliminary testing of the prototype and experimental monitoring of sand interfacial slide which mimics soil–rock interfacial landslide were performed to demonstrate the performance of the developed sensor prototype with adaptive amplification and enhanced sensitivity.

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