White pigments

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gerhard Pfaff
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Visible Light ◽  
Surrounding Medium ◽  
Inorganic Pigments ◽  
White Pigment ◽  
The Difference

Abstract White pigments are inorganic pigments, whose optical action is mainly based on non-selective light scattering. White pigments do not show absorption in the range of visible light, but have high scattering power leading to high hiding power in their applications. The greater the difference between the refractive index of the white pigment and that of the surrounding medium, the higher the scattering power.

scholarly journals Spectropolarimetric analyses of optical single mode SU8 waveguide layers

2015 ◽  
Vol 63 (2) ◽  
pp. 349-352 ◽  
Author(s):  
K. Gut ◽  
Z. Opilski
Keyword(s):  
Refractive Index ◽  
Visible Light ◽  
Spectral Distribution ◽  
Effective Refractive Index ◽  
Planar Waveguide ◽  
Single Mode ◽  
The Difference

Abstract The paper presents the principle of the operation of a spectropolarimetric interferometer. In a planar waveguide orthogonal modes of the TE and TM types can be excited for the entire visible light. During the propagation the difference of the phases between the modes was determined, which is the function of the length of the path of propagation, the difference of the effective refractive index (NTM-NTE) and the wavelength. At the output of this system the spectral distribution of intensity was recorded, the shape of which depends on the value of the refractive index of the cover of the waveguides

Stress Whitening in Polypropylene. I. Light Scattering Theory and Model Experiments

1995 ◽  
Vol 60 (11) ◽  
pp. 1875-1887 ◽  
Author(s):  
Jaroslav Holoubek ◽  
Miroslav Raab
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Incident Light ◽  
Polymeric Materials ◽  
Wavelength Dependence ◽  
Theoretical Background ◽  
Surrounding Matrix ◽  
Embedded Particles ◽  
The One ◽  
Stress Whitening

Theoretical background for an optical method is presented which makes it possible to distinguish unambiguously between voids and particles as light scattering sites in polymeric materials. Typical dependences of turbidity as a function of diameter of scattering elements, their volume fractions and also turbidity curves as a function of the wavelength of the incident light were calculated, based both on the Lorenz-Mie theory and the fluctuation theory. Such dependences calculated for polypropylene-containing voids on the one hand and particles, differing only slightly from the surrounding matrix in their refractive index, on the other hand, are markedly different. The most significant results are: (i) Turbidity is at least by two orders of magnitude larger for voids in comparison to embedded particles of ethylene-propylene (EPDM) rubber of the same size, concentration and at the same wavelength. (ii) The wavelength dependence of turbidity for EPDM particles and the inherent refractive index fluctuations in the polypropylene matrix is much steeper as compared to voids for all considered diameters (0.1-10 μm). Thus, the nature of stress whitening in complex polymeric materials can be determined from turbidity measurements.

scholarly journals Hybrid Grating in Reduced-Diameter Fiber for Temperature-Calibrated High-Sensitivity Refractive Index Sensing

2019 ◽  
Vol 9 (9) ◽  
pp. 1923
Author(s):  
Biqiang Jiang ◽  
Zhen Hao ◽  
Dingyi Feng ◽  
Kaiming Zhou ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Surrounding Medium ◽  
High Sensitivity ◽  
Fiber Grating ◽  
Bragg Resonance ◽  
Core Mode ◽  
Promising Alternative ◽  
Sensing Applications ◽  
Highly Sensitive

We propose and experimentally demonstrate a hybrid grating, in which an excessively tilted fiber grating (Ex-TFG) and a fiber Bragg grating (FBG) were co-inscribed in a reduced-diameter fiber (RDF). The hybrid grating showed strong resonances due to coupling among core mode and a set of polarization-dependent cladding modes. This coupling showed enhanced evanescent fields by the reduced cladding size, thus allowing stronger interaction with the surrounding medium. Moreover, the FBG’s Bragg resonance confined by the thick cladding was exempt from the change of the surrounding medium’s refractive index (RI), and then the FBG can work as a temperature compensator. As a result, the Ex-TFG in RDF promised a highly sensitive RI measurement, with a sensitivity up to ~1224 nm/RIU near the RI of 1.38. Through simultaneous measurement of temperature and RI, the temperature dependence of water’s RI is then determined. Therefore, the proposed hybrid grating with a spectrum of multi-peaks embedded with a sharp Bragg resonance is a promising alternative for the simultaneous measurement of multi-parameters for many RI-based sensing applications.

Low-Cost Heat Insulating Film Design for BIPV Modules Based on Multi-Layer Inorganic Materials

2012 ◽  
Vol 452-453 ◽  
pp. 1424-1428
Author(s):  
Han Min Tian ◽  
Li Jia Guo ◽  
Wen Feng Duan ◽  
Rui Xia Yang ◽  
Feng Lan Tian
Keyword(s):  
Refractive Index ◽  
Visible Light ◽  
Absorption Rate ◽  
Heat Insulation ◽  
Low Cost ◽  
Heat Rate ◽  
Optimum Combination ◽  
Inorganic Materials ◽  
Tempered Glass ◽  
Glass Panel

By analyzing the transmitionce and heat rate of insulating antireflection films conposed by refractive-index adjustable SiO2 layer and TiO2 layers, the optimum combination of antireflection films of BIPV is obtained. The absorption rate at the ultraviolet part that wavelenght excessive inadequate 400nm of the optimized fils is 99.9%, which are directly designed on the surface of the low iron tempered glass panel of BIPV, and in the wavelength range 400nm-800nm, the visible light transmitionce rate is up to 99.5%, and the heat that wavelenght excessive 800nm is reflected of 20%. For the multilayer heat insulation films are composed with the same kind of material while with different refractive indexes, there is no projecting stress between these films and no constraints during the production process of different films for the possible low cost heat insulating of BIPV.

SIZE-DEPENDENT NONRESONANT THIRD-ORDER NONLINEAR SUSCEPTIBILITIES OF CdS CLUSTERS FROM 7 TO 120 Å

1992 ◽  
Vol 01 (04) ◽  
pp. 683-698 ◽  
Author(s):  
YING WANG ◽  
NORMAN HERRON
Keyword(s):  
Refractive Index ◽  
Quantum Confinement ◽  
Optical Switching ◽  
Quantum Confinement Effect ◽  
Surrounding Medium ◽  
Confinement Effect ◽  
Third Order ◽  
Size Dependent ◽  
Size Regime ◽  
Fundamental Wavelength

We report the third-order nonlinear susceptibilities χ(3) of CdS clusters (quantum dots) from 7 to 120 Å, measured by third-harmonic generation technique at a fundamental wavelength of 1.91 µm. In the size regime studied, the value of χ(3) first increases with cluster size and then levels off for cluster diameter larger than 60 Å. The volume normalized χ(3) of CdS cluster is about a factor of 2 higher than that of the bulk. These data can be explained by the enhancement in electric field inside the clusters due to the dielectric confinement effect. The size and wavelength dependences of this local field effect have been calculated for CdS clusters. Several trends in the nonresonant χ(3) can be identified: (i) In the absence of quantum confinement effect, the magnitude of χ(3) should be constant in the < 200 Å size regime. It then increases with increasing particle size until the structural resonance regime is reached. (ii) The magnitude of χ(3) can be enhanced by either lowering the refractive index of the surrounding medium or raising the refractive index of the semiconductors. (iii) Quantum confinement, which shifts the band gap to the blue and lowers the refractive index of the semiconductor clusters, reduces the nonresonant χ(3). This is in direct contrast to the resonant nonlinearity which is enhanced by the quantum-confinement effect. Finally, we discuss the size-dependent figure-of-merit of CdS composites for all-optical switching.

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