scholarly journals Measurement of Wavelength and Temperature-Dependent Optical Properties of Thermochromic Pigments

2017 ◽  
Vol 72 (2) ◽  
pp. 297-304 ◽  
Author(s):  
Jianying Hu ◽  
Xiong (Bill) Yu
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Transition Temperature ◽  
Optical Constants ◽  
Temperature Dependent ◽  
Thermochromic Material ◽  
Different Temperatures ◽  
Cubic Polynomial ◽  
Thermochromic Pigment

Thermochromic material is a substance that is capable of changing reversibly the color as the temperature rises. Therefore, the optical spectrum of thermochromic material is responsive to the environmental temperature. In this study, the temperature-dependent optical constants of thermochromic pigments over the wavelength of 350–1800 nm were investigated. Three kinds of thermochromic pigments featured with black, blue, and red colors at room temperature were suspended in water and the light reflection and transmission of the suspensions at different temperatures were measured by a multifunctional spectrophotometer. It was found that below the transition temperature of thermochromic material, the refractive index was 2.1–2.5, 2.2–2.6, and 2.0–2.4 over the wavelength range of 350–1800 nm for black, blue, and red thermochromic pigment, respectively, while above the transition temperature it reached 2.3–2.7, 2.4–2.9, and 2.4–2.7, respectively. It was also observed that the relationship between refractive index of thermochromic pigment and wavelength follows the cubic polynomial function. Furthermore, the extinction coefficient is in the range of 1 × 10−5–1.2 × 10−4 for all thermochromic pigments and remains approximately stable at different temperatures. The determination of optical constants of thermochromic pigments provides essential parameters in the modeling of light scattering and absorption by pigment particles to further fine-tune the optical properties of thermochromic coating.

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

Study the Effect of Heat Treatment and Pressure on some the Optical Properties of the Pure PVA Nano Polymer

2021 ◽  
Vol 900 ◽  
pp. 16-25
Author(s):  
Tabarak Mohammed Awad ◽  
May A.S. Mohammed
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Polyvinyl Alcohol ◽  
Complex Dielectric Constant ◽  
Different Temperatures ◽  
German Origin ◽  
Increasing Temperature

In this study, some optical properties were studied of the pure vinyl polyvinyl alcohol (PVA) nanopolymer (German origin). Under the influence of different temperatures and pressures of PVA. Where 25 samples were prepared for the purpose of conducting the research. Which studied the study of these samples was done by recording the absorbance and transmittance spectra of the wavelengths (200-900) nm. From them, absorbance, transmittance, reflectivity, absorption coefficient, refractive index, extinction coefficient, complex dielectric constant were calculated. At different temperatures (25,40, 80, 120, 160)°C. And with different pressures within the range (7.5,8,8.5,9,9.5) MPa. The results are that the permeability of the polymer (PVA) at different temperatures for each pressure decreases with increasing temperature, and that all other calculated optical properties increase with increasing temperature.

scholarly journals Determination of glass transition temperature using temperature dependent signal from a cryogenic photopyroelectric instrument

2019 ◽  
Vol 676 ◽  
pp. 7-12 ◽  
Author(s):  
Allen Mathew ◽  
Fabrice Goutier ◽  
Benoit Escorne ◽  
Abdelaziz Elass ◽  
Gérard Louis ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Dependent ◽  
Dependent Signal

The use of a slit in determining refractive indices with the microscope

1917 ◽  
Vol 18 (84) ◽  
pp. 130-132
Author(s):  
John William Evans
Keyword(s):  
Crystal Structure ◽  
Refractive Index ◽  
Optical Properties ◽  
Critical Angle ◽  
Total Reflection ◽  
Index Of Refraction ◽  
Refractive Indices ◽  
Object Image ◽  
Ordinary Object

Certain optical properties of crystals, and more particularly the refractive index, may be determined either in the directions-image, often referred to as the 'image in convergent light', or in the ordinary object-image in which the object itself is seen. In the former case, in which the index of refraction is 'usually determined by means of the critical angle of total-reflection, every point in the image corresponds to a single direction of propagation of the wave-front through the crystal-structure and to the two corresponding directions of vibration. One of these can, however, be eliminated by the insertion of a nicol in an approximate position, and thus all ambiguity in the determination of the refractive index is removed.

Determination of optical constants and vibrational band intensities of liquids in the infrared using attenuated total reflexion

1967 ◽  
Vol 298 (1453) ◽  
pp. 160-177 ◽  
Keyword(s):  
Refractive Index ◽  
Carbon Tetrachloride ◽  
Working Conditions ◽  
Optical Constants ◽  
Carbon Disulphide ◽  
Absorption Bands ◽  
Total Reflexion ◽  
Solid Liquid Interface ◽  
Solid Liquid

The refractive index, and vibrational absorption band intensities, of some liquids have been determined by a new method involving attenuated total reflexion at a solid liquid interface. The principles of the method have been explained and the factors which determine a choice of optimal working conditions have been discussed. The method has been applied to absorp­tion bands of benzene, carbon tetrachloride, chloroform, bromoform, sym -tetrabromo-ethane, and carbon disulphide. Data have been obtained on the variation of refractive index across the absorption bands, and the computed band intensities have been compared with those obtained previously by other methods.

OPTICAL PROPERTIES OF THE OXIDATION OF Cu THIN FILMS PREPARED BY THERMAL EVAPORATION

2013 ◽  
Vol 20 (01) ◽  
pp. 1350011 ◽  
Author(s):  
GUOZHONG LAI ◽  
HUIQING LAN ◽  
SUANZHI LIN ◽  
YAN QU ◽  
FACHUN LAI
Keyword(s):  
Optical Properties ◽  
Layer Thickness ◽  
Optical Constants ◽  
Thermal Evaporation ◽  
Oxide Films ◽  
Cu Films ◽  
Different Temperatures ◽  
Optical Dielectric ◽  
Mixed Layers ◽  
Quartz Substrates

Copper films with 87 nm thickness were deposited on quartz substrates by thermal evaporation. In order to investigate the oxidation process, the Cu films were oxidized at different temperatures in air with different durations to obtain the complete and uncompleted copper oxide films. The structure and optical properties of the samples were studied by X-ray diffraction, scanning electron microscopy and spectrophotometer, respectively. It is found that the sample oxidized at 220°C for 200 min is Cu2O film with 106 nm thickness. Both the transmittance and reflectance of the samples increase with the increase of oxidation duration. The optical constants of the Cu film and the Cu2O film were retrieved by simulating the reflectance or transmittance based on the optical dielectric models. The optical constants of the Cu and Cu2O mixed layer with different composition were calculated by the effective medium theories. Adjusting the mixed layers composition and thickness, and Cu2O layer thickness, the transmittance and reflectance of the uncompleted oxidation films were simulated by optical multilayer design software. The results show that the uncompleted oxidation films consist of the Cu and Cu2O mixed layers and Cu2O layer. According to the parabolic rate law, the increase rate of Cu2O layer thickness for the uncompleted oxide films at 200°C is 1.6 nm s-1/2.

scholarly journals Study the Optical Properties of Polyaniline-PEDOT Nano Composite

2018 ◽  
Vol 6 (5) ◽  
Author(s):  
Maan A. Saleh ◽  
Abdulazeez O.Mousa ◽  
Mohammed Hadi Shinen
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Electromagnetic Wave ◽  
Absorption Coefficient ◽  
Optical Constants ◽  
Energy Gap ◽  
Absorption Factor ◽  
Nano Composite ◽  
Large Molecules ◽  
Before And After

The study includes the recording the absorption and permeability spectra of a combination of polyaniline compound solution with poly(3,4-ethylenedioxythiophene) PEDOT and calculating the absorption factor and other optical constants. These samples were attended to different concentrations (0.01%,0.02%,0.03%) of PEDOT added to polyaniline. The values of absorbance, the refractive index values of pure polymer and its additives are increasing with the increase of the concentrations of these polymer,noting that the increment of absorption coefficient values under the influence of addition caused by increasing density of the solutions as a result of the increased concentrations, that led to the increase of light absorbed because the interaction of the electromagnetic wave and the large molecules of the polymer increases with concentration,the results show that decreasing in the values of transmittance with all concentrations, the values of reflectance are increases with increasing concentration before and after the doping, the results showed decrease energy gap with increasing ratio of doping.

Optical properties of Al-doped ZnO thin films obtained by the method of high-frequency magnetron sputtering

2021 ◽  
pp. 2150189
Author(s):  
A. Kashuba ◽  
H. Ilchuk ◽  
R. Petrus ◽  
I. Semkiv ◽  
O. Bovgyra ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
High Frequency ◽  
Optical Constants ◽  
Zno Thin Films ◽  
Optical Parameters ◽  
Single Oscillator ◽  
Doped Zno

The optical constants and thickness of Al-doped ZnO (ZnO:Al(2.5 wt.%)) thin films prepared by high-frequency magnetron sputtering method are determined. ZnO:Al thin films are crystallized in the hexagonal structure from XRD studies. The optical constants and the bandgap of the films under study have been determined. Optical properties (refractive index [Formula: see text], absorption coefficient [Formula: see text], extinction coefficient [Formula: see text], dielectric functions [Formula: see text] and optical conductivity [Formula: see text]) of thin films and thickness [Formula: see text] can be determined from the transmission spectrum. The dispersion of the refractive index was explained using a single oscillator model. Single oscillator energy and dispersion energy are obtained from fitting. Optical parameters of the films were determined using the Cauchy, Sellmeier and Wemple models. The increasing value of dispersion parameter for polycrystalline thin films than for single crystals is observed. The fundamental absorption edge position (3.26 eV) in the transmittance spectrum of studied thin films corresponds to the values that are typical for ZnO:Al compound. No significant increase of the bandgap width was revealed by comparing ZnO:Al thin films with the known results of the optical studies of ZnO thin films. Possible reasons of such behavior were analyzed and the influence of bandgap increase on spectral behavior of optical functions are investigated. The material optical parameters such as normalized integrated transmission, zero and high-frequency dielectric constant, density of state effective mass ratio were also calculated.

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