Optical Interference Filters By Sol-Gel Processing

1990 ◽  
Vol 180 ◽  
Author(s):  
J.L. Keddie ◽  
E.P. Giannelis
Keyword(s):  
Refractive Index ◽  
Rutherford Backscattering Spectrometry ◽  
Incident Light ◽  
Sol Gel ◽  
Theoretical Modeling ◽  
Optical Interference ◽  
Interference Filters ◽  
The Individual ◽  
Gel Processing ◽  
Good Agreement

ABSTRACTOptical interference filters have been synthesized by sol-gel. The selected filter is a multilayer of alternating TiO2 and SiO2 films. In transmission, the filter edge depends on the angle of incident light, which can be tailored through control of thickness and refractive index of the individual films. Theoretical modeling of the filter with film thicknesses obtained by Rutherford backscattering spectrometry is in good agreement with the experimental optical response.

scholarly journals Comparison of AERONET and SKYRAD4.2 inversion products retrieved from a Cimel CE318 sunphotometer

2012 ◽  
Vol 5 (3) ◽  
pp. 569-579 ◽  
Author(s):  
V. Estellés ◽  
M. Campanelli ◽  
M. P. Utrillas ◽  
F. Expósito ◽  
J. A. Martínez-Lozano
Keyword(s):  
Refractive Index ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Asymmetry Parameter ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Research Network ◽  
High Turbidity ◽  
The Individual ◽  
Good Agreement

Abstract. SKYNET is an international research network of ground based sky – sunphotometers for the observation and monitoring of columnar aerosol properties. The algorithm developed by SKYNET is called SKYRAD.pack, and it is used on Prede instruments only. In this study, we have modified the SKYRAD.pack software in order to adapt it to Cimel sunphotometers. A one month database of Cimel data obtained at Burjassot (Valencia, Spain) has been processed with this program and the obtained inversion products have been compared with AERONET retrievals. In general, the differences found were consistent with the individual error assessments for both algorithms. Although the aerosol optical depth compared well for any aerosol burden situation (rmsd of 0.002–0.013 for all wavelengths), inversion products such as the single scattering albedo, refractive index and asymmetry parameter compared better for higher turbidity situations. The comparison performed for cases with an aerosol optical depth at 440 nm over 0.2 showed rms differences of 0.025–0.049 for single scattering albedo, 0.005–0.034 for the real part of refractive index, 0.004–0.007 for the imaginary part of the refractive index and 0.006–0.009 for the asymmetry parameter. With respect to the volume distributions, the comparison also showed a good agreement for high turbidity cases (mainly within the 0.01–7 μm interval) although the already known discrepancy in the extremes of the distribution was still found in 40% of the cases, in spite of eliminating data and instrumental differences present in previous studies.

Analysis of depth profiles of sol-gel derived multilayer coatings by Rutherford backscattering spectrometry and by cross-sectional transmission electron microscopy1

1991 ◽  
Vol 6 (4) ◽  
pp. 835-839 ◽  
Author(s):  
Carol L. Schutte ◽  
Patrick M. Smith ◽  
George M. Whitesides
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
Sol Gel ◽  
Compositional Analysis ◽  
Rutherford Backscattering ◽  
Multilayer Coatings ◽  
Cross Sectional ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Transmission Electron ◽  
The Individual

This paper describes the preparation and compositional analysis of multilayer thin-film coatings prepared using sol-gel techniques. Alternate layers were labeled with an iron tag, derived from hydrolyzed 1,1'-bis(triethoxysilyl)ferrocene. Iron-free layers were composed of SiO2 derived from hydrolyzed tetraethylorthosilicate (TEOS). Analyses of these systems were based on Rutherford Backscattering Spectrometry (RBS) and Cross-Sectional Transmission Electron Microscopy (XTEM). The depth profile of iron, measured by RBS, yielded thicknesses (1000–1600 Å) for the individual layers that could be verified independently by XTEM.

Optical Interference Filters Made of Porous Silicon

1996 ◽  
Vol 431 ◽  
Author(s):  
M. Thönissen ◽  
M. G. Berger ◽  
M. Krüger ◽  
S. Billat ◽  
R. Arens-Fischer ◽  
...  
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Current Density ◽  
Layer Structure ◽  
Single Layer ◽  
Bragg Reflectors ◽  
Optical Interference ◽  
Interference Filters ◽  
Thickness Measurements ◽  
Reflectance Measurements

AbstractPorous silicon (PS) layers can easily be formed by an electrochemical etch process using a mixture of hydrofluoric acid (HF) and ethanol. The microstructure and porosity of the layers depend on the HF concentration, the doping level of the substrate and the current density applied during the etch process. Changing the current density during the etch process will result in a well defined layer structure consisting of layers with different porosities. Each single layer can be treated as an effective medium exhibiting a refractive index depending mainly on the porosity of the layer. Using reflectance measurements we have investigated the dependence of the refractive index of PS layers on the formation current density for different substrates. In addition the etch rate was determined by thickness measurements with an electron microscope. Based on these results various kinds of optical interference filters were studied. We have formed samples consisting of discrete single layers with different porosities (e.g. Bragg reflectors) as well as samples with continuous variation of the refractive index (rugate filters). Combining these PS filters with standard photolithography steps, microoptical devices such as spectral sensitive photodiodes can be realized.

Diffuse reflectance of retinal tapeta lucida, with special reference to drums (Sciaenidae)

1981 ◽  
Vol 59 (2) ◽  
pp. 271-284 ◽  
Author(s):  
R. Wang ◽  
J. A. C. Nicol ◽  
H. J. Arnott
Keyword(s):  
Refractive Index ◽  
Light Absorption ◽  
Visual Pigment ◽  
Diffuse Reflectance ◽  
Pigment Epithelium ◽  
Incident Light ◽  
Model System ◽  
Maximal Absorption ◽  
Reflection Of Light ◽  
Good Agreement

Reflection of light by ocular tapeta lucida of drums (Sciaenidae) was studied in Cynoscion arenarius Ginsburg, C. nebulosus (Cuvier), Micropogon undulatus (L.) and Leiostomus xanthurus Lacèpéde. The tapetum is located in the pigment epithelium of the eye, is matt white, and behaves as a uniform diffuser. The pigment epithelium contains densely packed tapetal spheres; these are randomly arranged, have a diameter of about 0.4 μm and contain a lipid that has a refractive index of 1.50. Because of their dense packing they backscatter much of the incident light. Diffuse reflectance is about 50%. Measured values of reflectance are compared with those computed for a model system having the same physical characteristics, and they are in good agreement. The optical density of the visual pigment at the wavelength of maximal absorption (λ 510 nm) is 0.33, and the tapetum increases light absorption in the dark-adapted eye by a factor of 1.3. Reflectance of croaker tapetum is compared with reflectances of tapeta of Lepisosteus, Arius, and Notopterus afer, which contain different reflecting materials.

New high-refractive-index organic/inorganic hybrid materials from sol-gel processing

1991 ◽  
Vol 24 (11) ◽  
pp. 3449-3450 ◽  
Author(s):  
B. Wang ◽  
G. L. Wilkes ◽  
J. C. Hedrick ◽  
S. C. Liptak ◽  
J. E. McGrath
Keyword(s):  
Refractive Index ◽  
Hybrid Materials ◽  
Sol Gel ◽  
High Refractive Index ◽  
Inorganic Hybrid ◽  
Gel Processing

scholarly journals Comparison of AERONET and SKYRAD4.2 inversion products retrieved from a Cimel CE318 sunphotometer

2011 ◽  
Vol 4 (6) ◽  
pp. 6883-6913 ◽  
Author(s):  
V. Estellés ◽  
M. Campanelli ◽  
M. P. Utrillas ◽  
F. Expósito ◽  
J. A. Martínez-Lozano
Keyword(s):  
Refractive Index ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Asymmetry Parameter ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Research Network ◽  
High Turbidity ◽  
The Individual ◽  
Good Agreement

Abstract. SKYNET is an international research network of ground based sky-sunphotometers for the observation and monitoring of columnar aerosol properties. The algorithm developed by SKYNET is called SKYRAD.pack, and so far it has been used on Prede instruments only. In this study we have modified the SKYRAD.pack software in order to adapt it to Cimel sunphotometers. A one month database of Cimel data obtained at Burjassot (Valencia, Spain) has been processed with this program and the obtained inversion products have been compared with AERONET retrievals. In general, the differences found were consistent with the individual error assessments for both algorithms. Although the aerosol optical depth compared well for any aerosol burden situation (rmsd of 0.002–0.013 for all wavelengths), inversion products such as the single scattering albedo, refractive index and asymmetry parameter compared better for higher turbidity situations. The comparison performed for cases with an aerosol optical depth at 440 nm over 0.2 showed rms differences of 0.025–0.049 for single scattering albedo, 0.005–0.034 for the real part of refractive index, 0.004–0.007 for the imaginary part of the refractive index, and 0.006–0.009 for the asymmetry parameter. In respect to the volume distributions, the comparison also showed a good agreement for high turbidity cases (mainly within the 0.01–7 μm interval) although the already known discrepancy in the extremes of the distribution was still found in 40% of cases, in spite of eliminating data and instrumental differences present in previous studies.

scholarly journals Demonstration of optical interference filters utilizing tunable refractive index layers

2010 ◽  
Vol 18 (S4) ◽  
pp. A594 ◽  
Author(s):  
David J. Poxson ◽  
Frank W. Mont ◽  
Martin F. Schubert ◽  
Jong Kyu Kim ◽  
Jaehee Cho ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Interference ◽  
Interference Filters ◽  
Tunable Refractive Index

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

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