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Investigation of optical and dielectric properties of CsPbI3 inorganic lead iodide perovskite thin film
摘要： This experimental work reports refractive index, extinction coe?cients, and dielectric functions at different incident angles in visible range for the ?rst time. The refractive index of CsPbI 3 thin ?lm is 2.46 at 435 nm with this result implies that Cs based lead halide solar cells may be, ideal antire?ection coating for many tandem solar cells. Thus lower refractive index of CsPbI 3 inorganic perovskite material is bene?cial for perovskite device fabrications because of the minimum light looses to re?ection at the front of the active layer. Furthermore microstructure of the cubic phase Pm-3 m was investigated by X-ray di?raction. CsPbI 3 perovskite thin ?lm showed the sharp absorption edge and PL emission near infrared region with direct band gap of 1.67 eV with high color purity of red emission. In addition, the higher dielectric function value of CsPbI 3 , will helps to many optoelectronic devices.
关键词： Ellipsometry,Dielectric function,Inorganic perovskite,Refractive index
更新于2025-09-09 09:28:46
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Surface engineering of polystyrene–cerium oxide nanocomposite thin films for refractive index enhancement
摘要： Polymer nanocomposites have gained much importance in the field of optoelectronics due to their unique optical properties. Refractive index engineering using nanoparticles is an effective strategy that could be applied for the fabrication of optical devices. Herein, we report three different strategies which are employed to enhance the refractive index of polymer thin films. These include incorporating cerium oxide nanoparticles onto the polystyrene matrix, secondly adding cerium oxide nanoparticles onto the cross-linkable polystyrene and thirdly by embedding functionalized cerium oxide nanoparticles onto the cross-linkable polystyrene. Refractive index of the polystyrene thin films was enhanced by dispersing neat CeO2 nanoparticles and functionalized CeO2 nanoparticles into the polystyrene matrix. 1.38% enhancement in the refractive index of the polymer nanocomposite thin films could be achieved using our technique. The blending of polystyrene with cerium oxide nanoparticle presents a prospective way to engineer the refractive index of polymer thin films. We firmly believe that the study will be an effective guide towards future research in the area of surface engineering of polymer thin films for refractive index enhancement.
关键词： Refractive index,Polystyrene,Polymer nanocomposites,Thin films,Cerium oxide,Surface engineering
更新于2025-09-09 09:28:46
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Ultrasensitive Refractometry <i>via</i> Supercritical Angle Fluorescence
摘要： Refractometry, namely, the measurement of refractive index (RI), provides information about various sample properties such as concentrations and molecular structure. One physical phenomenon which enables precise determination of a sample’s RI in a microscope is the supercritical-angle fluorescence. This effect is observed when the fluorescence from an emitter near a glass-medium interface is captured by an objective lens with a high numerical aperture. The materials’ index mismatch creates a distinguishable transition in the intensity pattern at the back focal plane of the objective that changes proportionally to the RI of the media. Here, we present a refractometry approach in which the fluorophores are preattached to the bottom surface of a microfluidic channel, enabling highly-sensitive determination of the RI using tiny amounts of liquid (picoliters). With this method, we attained a standard deviation of 3.1 × 10?5 and a repeatability of 2.7 × 10?5 RI units. We first determine the capabilities of the device for glycerol-water solutions, then demonstrate the relevance of our system for monitoring changes in biological systems. As a model system, we show that we can detect single bacteria (Escherichia coli) and measure population growth.
关键词： refractive-index,refractometry,bacterial growth,microfluidics,supercritical angle fluorescence,bio-detection
更新于2025-09-09 09:28:46
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[IEEE 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - Tiruchengode, India (2018.3.2-2018.3.3)] 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - Study the Complex Dielectric and Energy loss function of Graphene oxide nanostructures using linear optical constant
摘要： In this paper, the linear optical properties of Graphene oxide nanostructure have been calculated depending on the absorbance spectra at wavelength range (200-800 nm). The linear optical constants such as refractive index (n) and extraction coefficient (k) are calculated for analyzing the Complex dielectric function. The surface and volume vitality energy loss has been studied by the dielectric measurement.Present speculative concepts were used to discuss the attained results.
关键词： Loss Function,Refractive Index,Dielectric Constant
更新于2025-09-09 09:28:46
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Simultaneous measurement of strain, temperature and refractive index based on a fiber Bragg grating and an in-line Mach–Zehnder interferometer
摘要： A simple sensor for simultaneous measurement of strain, temperature and refractive index (RI) is proposed and demonstrated. The sensor is based on a fiber Bragg grating (FBG) combined with an in-line Mach-Zehnder interferometer (MZI). MZI is formed by introducing a section of thinned core fiber (TCF) between two segments of multimode fiber (MMF). The two MMFs act as couplers that can excite high-order modes and recouple core mode and high-order modes into lead-out SMF, the function of this structure is to form inter-modes interference. The maximum interference fringe visibility exceed 20 dB. By monitoring the wavelength shifts of FBG and interference dips, simultaneous measurement of strain, temperature and RI can be achieved. The experimental results show that the maximum sensitivity of the sensor for strain, temperature and RI are -2.14 pm/με, 35.2 pm/°C and 32.93 nm/RIU, respectively. The proposed sensor has the advantages of easy fabrication, high fringe visibility and high sensitivities. Therefore, it has potential applications in multi-parameters simultaneous measurement.
关键词： Temperature,Refractive index,Mach-Zehnder interferometer,Strain,Fiber Bragg grating
更新于2025-09-09 09:28:46
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Optical properties of Ca(MoxW1-x)O4: Eu3+ heteropoly salt phosphors
摘要： The Ca(MoxW1-x)O4: Eu3+ phosphors with different concentrations were prepared by a precipitation process. The crystal structure was confirmed to be body centered tetragonal scheelite by X-ray diffraction measurement, and the morphology was characterized by field emission scanning electron microscopy. The photoluminescence measurement, including emission spectra, excitation spectra and fluorescence decay curves, were carried out. The results indicate that the best Mo:W ratio is 6:4, since the integral intensity of Eu3+ red emission (616 nm) in Ca(Mo0.6W0.4)O4: Eu3+ phosphors increases nearly 100% and 65% compared with the intensities in CaMoO4: Eu3+ and CaWO4: Eu3+. In this work, the best doping concentration is confirmed to be 25 mol% in Ca(Mo0.6W0.4)O4: Eu3+ phosphors. Exchange interaction was confirmed to dominate concentration quenching of Eu3+. Auzel's model was used to explain the self-generated quenching process of Eu3+ and obtain intrinsic lifetime of 5D0 level. Furthermore, a new method was proposed for calculating the refractive index.
关键词： photoluminescence,Eu3+,refractive index,heteropoly salt
更新于2025-09-09 09:28:46
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Applied Nanophotonics || Emerging nanophotonics
摘要： In this chapter a number of challenging trends in modern nanophotonics are highlighted that can be traced based on extensive research during the last decades. These are the colloidal technological platform, nanoplasmonics to enhance light–matter interaction, novel optical sensors based on nanostructures, advances toward the silicon photonic platform, negative refractive index materials, and single photon emitters. These novel trends and ideas, when seen together, provide a definite forecast for new exciting devices and systems to appear in the next decades and present nanophotonics as an extremely active and promising field of research and development.
关键词： silicon photonic platform,optical sensors,colloidal technological platform,negative refractive index materials,nanophotonics,single photon emitters,nanoplasmonics
更新于2025-09-09 09:28:46
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Anapole Resonances Facilitated by High Index Contrast between Substrate and Dielectric Nanodisk Enhance Vacuum Ultraviolet Generation
摘要： Anapole modes are known to be excited only in high-index nanoparticles. Here we show that the nanodisks made of dielectric materials with much lower refractive indices, such as LiNbO3, can generate anapole modes, provided that they are supported by metallic or near-zero-index substrate. The important parameter for exciting anapole mode is the index contrast between nanodisk and substrate, rather than the refractive index of the nanodisk. We numerically demonstrate highly efficient coherent generation of vacuum ultraviolet with the efficiency higher than 10-2 % based on the second-harmonic generation via the excitation of anapole modes in LiNbO3 nanodisks supported by aluminum substrate. Highly efficient vacuum ultraviolet nanosource proposed in this work can find important applications for spectroscopic and sensing purposes at the nanoscale.
关键词： Second-harmonic generation (SHG),Anapole mode,Refractive index,Nanodisks,Vacuum ultraviolet (VUV)
更新于2025-09-09 09:28:46
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Methods to retrieve the complex refractive index of aquatic suspended particles: going beyond simple shapes
摘要： The scattering properties of aquatic suspended particles have many optical applications. Several data inversion methods have been proposed to estimate important features of particles, such as their size distribution or their refractive index. Most of the proposed methods are based on the Lorenz–Mie theory to solve Maxwell’s equations, where particles are considered homogeneous spheres. A generalization that allows consideration of more complex-shaped particles is the T -matrix method. Although this approach imposes some geometrical restrictions (particles must be rotationally symmetrical) it is applicable to many life forms of phytoplankton. In this paper, three different scenarios are considered in order to compare the performance of several inversion methods for retrieving refractive indices. The error associated with each method is discussed and analyzed. The results suggest that inverse methods using the T -matrix approach are useful to accurately retrieve the refractive indices of particles with complex shapes, such as for many phytoplankton organisms.
关键词： Lorenz–Mie theory,scattering properties,T-matrix method,refractive index,aquatic suspended particles,phytoplankton
更新于2025-09-09 09:28:46
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Temperature-Dependent Refractive Index of Quartz at Terahertz Frequencies
摘要： Characterisation of materials often requires the use of a substrate to support the sample being investigated. For optical characterisation at terahertz frequencies, quartz is commonly used owing to its high transmission and low absorption at these frequencies. Knowledge of the complex refractive index of quartz is required for analysis of time-domain terahertz spectroscopy and optical pump terahertz probe spectroscopy for samples on a quartz substrate. Here, we present the refractive index and extinction coefficient for α-quartz between 0.5 THz and 5.5 THz (17–183 cm?1) taken at 10, 40, 80, 120, 160, 200 and 300 K. Quartz shows excellent transmission and is thus an ideal optical substrate over the THz band, apart from the region 3.9 ± 0.1 THz owing to a spectral feature originating from the lowest energy optical phonon modes. We also present the experimentally measured polariton dispersion of α-quartz over this frequency range.
关键词： Terahertz,Quartz,Refractive index,Dispersion,Silica,Optical pump terahertz probe OPTPS,Time-domain spectroscopy,Polariton,SiO2
更新于2025-09-09 09:28:46