A Comparison of the Kubelka-Munk, Rozenberg, and Pitts-Giovanelli Methods of Analysis of Diffuse Reflectance for Several Model Systems

1983 ◽  
Vol 37 (4) ◽  
pp. 348-354 ◽  
Author(s):  
Harry G. Hecht
Keyword(s):  
Solid Solution ◽  
Refractive Index ◽  
Simple Form ◽  
Diffuse Reflectance ◽  
Model Systems ◽  
Methods Of Analysis ◽  
Single Method

Previous studies have shown that the Rozenberg and Pitts-Giovanelli methods are useful alternatives that may be applied to diffusely reflecting samples that fail to conform to the Kubelka-Munk theory. These studies are extended in the present work to include samples of three additional types, namely, those which incorporate the absorber in solid solution within the scattering particles, those in which the absorber is adsorbed on the surface of the scattering particles, and those consisting of a dye spotted on chromatographic papers. No single method of analysis is superior in all cases. Although the Pitts-Giovanelli method gives a much better fit in some cases, it fails to converge in others. For this reason the Kubelka-Munk and Rozenberg methods are preferred, particularly when applied to diffusers in a medium of refractive index n = 1. For such systems the Rozenberg equation reduces to a simple form that is as easy to apply as the Kubelka-Munk equation.

A combined experimental and theoretical optimization of the refractive index of NixMg1-xO solid solution for transparent nanocomposite applications

2020 ◽  
Vol 46 (12) ◽  
pp. 20061-20067
Author(s):  
Fatemeh Ashrafi ◽  
Hossein Mokhtari ◽  
S. Javad Hashemifar ◽  
Amir Alhaji
Keyword(s):  
Solid Solution ◽  
Refractive Index

scholarly journals XXXIV.—On the Vibrations of an Interrupted Medium

1844 ◽  
Vol 15 (4) ◽  
pp. 511-539
Author(s):  
Philip Kelland
Keyword(s):  
Simple Form ◽  
General Theorem ◽  
Experimental Result ◽  
Methods Of Analysis ◽  
The Law

In certain investigations which I have presented to the Society, relative to the modifications which light undergoes when it meets with a medium more dense than that in which it is travelling, the law of force has been supposed to be that of the inverse square of the distance. On re-examination of this subject, I find that there is no necessity for restricting the computations by the hypothesis of any particular law. The conclusions are perfectly independent of the law, provided one of the equations of reduction, the value of which it is not possible to compute by any known methods of analysis, be admitted as an experimental result. The object of the present Memoir is twofold : 1st, To present the analysis of the general theorem of vibrations at the surface of an interrupted medium in its most simple form; and, 2d, To apply the results to the case of reflection unaccompanied by refraction.

The Anisotropy Factor in Dense Scattering Media

1980 ◽  
Vol 34 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Harry G. Hecht
Keyword(s):  
Diffuse Reflectance ◽  
Wavelength Dependence ◽  
Anisotropic Scattering ◽  
Anisotropy Factor ◽  
Model Systems ◽  
Scattering Media ◽  
Good Account ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Single Scatter

It has been found that the Pitts-Giovanelli formula gives a good account of diffuse reflectance over a large concentration range in model systems containing a soluble absorber in a dispersion of nonabsorbing particles. However, a very anisotropic scattering phase function is required. The concentration and wavelength dependence of the anisotropy factor are explored in the present work and are found to follow trends which are reminiscent of those predicted on the basis of the Mie theory of single scatter. This lends further support to the applicability of the Pitts-Giovanelli method to model systems of this type.

Epitaxially induced secondary grain growth in Ti:LiNbO3 optical waveguides

1989 ◽  
Vol 47 ◽  
pp. 424-425
Author(s):  
M. A. McCoy
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Refractive Index ◽  
Lithium Niobate ◽  
Grain Growth ◽  
Optical Waveguides ◽  
Waveguide Devices ◽  
Transmission Electron ◽  
Electro Optic

Lithium niobate (LiNbO3) is one of the most promising materials for use in hybrid optical waveguide devices because of its high electro-optic coefficient and its availability as large single crystals. Optical waveguides in LiNbO3 are most commonly made by Ti indiffusion in which strips of Ti metal (between 10 and 100 nm thick) are deposited on a single crystal LiNbO3 substrate. The device is then heated to temperatures around 1000°C typically for 6 hours. During this time, the Ti diffuses into the LiNbO3 to form a Ti-rich LiNbO3 solid solution. This solid solution has a higher refractive index than the substrate and forms the waveguide region. Factors controlling the indiffusion process, however, are not very well understood and very little is known about the microstructural changes which occur during Ti indiffusion. In this study, the microstructure of Ti:LiNbO3 optical waveguides was examined as a function of time and temperature using transmission electron microscopy (TEM).

1,3-Dimethyl-tetrakis(2-triphenylsilylethyl)dimethyldisiloxane: a new carbosilane for the preparation of high-refractive-index films

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sacha Legrand ◽  
Ari Kärkkäinen
Keyword(s):  
Refractive Index ◽  
Diffuse Reflectance ◽  
Gel Permeation Chromatography ◽  
2D Nmr ◽  
High Refractive Index ◽  
Diffuse Reflectance Infrared Spectroscopy ◽  
Gel Permeation ◽  
One Step ◽  
Diffuse Reflectance Infrared ◽  
Very High

Abstract A new carbosilane has been synthesised in one step by hydrosilylation of 1,3-dimethyl-tetravinyldisiloxane with triphenyl silane. The new carbosilane has been characterized by 1D and 2D NMR, MS, and Gel Permeation Chromatography (GPC). The new carbosilane has been spin-coated on silicon wafers to prepare a film with very high refractive index (μ = 1.520) and excellent hydrophobicity. The film has also been analysed by Diffuse Reflectance Infrared Spectroscopy (DRIFT). The preparation of the new carbosilane does not generate waste, and its application can be easily scaled-up. Consequently, the new precursor is likely to be very useful for industrial optoelectronic applications.

Cationic Ordering, Solid Solution Domain, and Diffuse Reflectance in Fe2WO6 Polymorphs

2021 ◽  
Author(s):  
Stéphane Caubergh ◽  
Nami Matsubara ◽  
Françoise Damay ◽  
François Fauth ◽  
Dmitry D. Khalyavin ◽  
...  
Keyword(s):  
Solid Solution ◽  
Diffuse Reflectance ◽  
Solution Domain

scholarly journals Refractive index matched, nearly hard polymer colloids

2019 ◽  
Vol 475 (2226) ◽  
pp. 20180763 ◽  
Author(s):  
Gregory N. Smith ◽  
Matthew J. Derry ◽  
James E. Hallett ◽  
Joseph R. Lovett ◽  
Oleksander O. Mykhaylyk ◽  
...  
Keyword(s):  
Refractive Index ◽  
Diblock Copolymer ◽  
Volume Fraction ◽  
Hard Spheres ◽  
Scattered Light ◽  
Degree Of Polymerization ◽  
Model Systems ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Crucial Difference

Refractive index matched particles serve as essential model systems for colloid scientists, providing nearly hard spheres to explore structure and dynamics. The poly(methyl methacrylate) latexes typically used are often refractive index matched by dispersing them in binary solvent mixtures, but this can lead to undesirable changes, such as particle charging or swelling. To avoid these shortcomings, we have synthesized refractive index matched colloids using polymerization-induced self-assembly (PISA) rather than as polymer latexes. The crucial difference is that these diblock copolymer nanoparticles consist of a single core-forming polymer in a single non-ionizable solvent. The diblock copolymer chosen was poly(stearyl methacrylate)–poly(2,2,2-trifluoroethyl methacrylate) (PSMA–PTFEMA), which self-assembles to form PTFEMA core spheres in n -alkanes. By monitoring scattered light intensity, n -tetradecane was found to be the optimal solvent for matching the refractive index of such nanoparticles. As expected for PISA syntheses, the diameter of the colloids can be controlled by varying the PTFEMA degree of polymerization. Concentrated dispersions were prepared, and the diffusion of the PSMA–PTFEMA nanoparticles as a function of volume fraction was measured. These diblock copolymer nanoparticles are a promising new system of transparent spheres for future colloidal studies.

scholarly journals Silica Sol-gel Coatings with Improved Light Transmittance and Stability

2017 ◽  
Author(s):  
Lenke Kócs ◽  
Emőke Albert ◽  
Borbála Tegze ◽  
Márta Kabai-Faix ◽  
Csaba Major ◽  
...  
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
Temporal Stability ◽  
Storage Period ◽  
Dip Coating ◽  
Silica Sol ◽  
Model Systems ◽  
Light Transmittance ◽  
Silica Coatings ◽  
Glass Substrates

Silica sol-gel coatings on different substrate materials and their use as model systems have been studied. Mesoporous silica coatings with thicknesses of 85 - 135 nm and porosity of 18 ˗ 37% were prepared by dip-coating on polycarbonate and glass substrates. In order to eliminate the shrinkage of the porous structure acid or base vapour treatment was applied. Thickness and refractive index of the coatings were determined by analysing the transmittance spectra of the samples. Ellipsometric porosimetry measurements were carried out to determine the porosity, pore radius distribution, thickness and refractive index. The thickness of the samples was further confirmed by scanning electron microscopy. The adsorption capacity of the porous coatings was also studied by dye impregnation tests. The temporal stability of the samples was investigated by UV-Vis spectrometry and it was found that the advantageous optical properties (Tmax = 98 – 99%) of the samples remained constant even after a 1 year storage period.

A Critical Evaluation of Three Types of Diffuse Reflectance Infrared Accessories

1986 ◽  
Vol 40 (7) ◽  
pp. 974-978 ◽  
Author(s):  
Paul W. Yang ◽  
Henry H. Mantsch ◽  
Fred Baudais
Keyword(s):  
Refractive Index ◽  
Diffuse Reflectance ◽  
Critical Evaluation ◽  
High Refractive Index ◽  
Polarization Characteristics ◽  
Diffuse Reflectance Infrared ◽  
Specular Component

Three geometrically different diffuse reflectance accessories were compared in terms of the throughput and ease of operation. The capability to discriminate the specular component against the diffuse reflectance component was investigated by the use of high refractive index samples. It was found that in all three accessories the specular as well as the diffuse reflectance components have similar reflection and polarization characteristics and that the specular component is primarily sample-dependent rather than accessory-dependent.

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