scholarly journals Analysis of the Processing‐Pressure Dependent Refractive Index of Polycarbonate by Transmission Measurements of Glass‐Filled Specimen

2019 ◽  
Vol 60 (3) ◽  
pp. 512-516
Author(s):  
Benedikt Roth ◽  
Wolfgang Wildner ◽  
Dietmar Drummer
Keyword(s):  
Refractive Index ◽  
Transmission Measurements

scholarly journals Light scattering of glass-particle filled matrices with similar refractive index

2018 ◽  
Vol 52 (30) ◽  
pp. 4231-4246 ◽  
Author(s):  
Wolfgang Wildner ◽  
Dietmar Drummer
Keyword(s):  
Refractive Index ◽  
Light Source ◽  
White Light ◽  
Scattered Light ◽  
Glass Particle ◽  
Refractive Indices ◽  
Mechanical And Thermal Properties ◽  
White Light Source ◽  
Transmission Measurements ◽  
Optical Appearance

If fillers can be added to transparent materials without losing transparency, then advantages like enhanced mechanical and thermal properties can be integrated. The investigated specimens consist of glass particles and refractive index oil as a model for transparent matrices with a very similar refractive index. Their optical properties and resulting limitations are described. Potential uses are also demonstrated by application-oriented optical testing. Besides a standard spectrometer, additional spectrometer setups were used. These include a diffuse as well as a collimated illumination and different sample positioning. Furthermore, the scattered light intensity was measured at different angles. This analysis reveals that composites with smaller particles transmit more light directly. In contrast, standard spectrometers indicate an increasing direct transmittance of composites with larger particles. They collect significant amounts of scattered light and, therefore, are not suitable for transmission measurements of such composites. The different positioning shows that all specimens exhibit very little scattering when placed directly on a diffuse light source. With a greater distance between specimen and light source, the scattering increases strongly. To display the composites' optical appearance, the light-dark-contrast of the diffuse white light source photographed behind the composite was analyzed. Both long and short distances between composite and light source lead to a precise image of the light source. Nevertheless, the white light source appears in the color of the wavelength with matching refractive indices at long distances.

scholarly journals Absorption Coefficient and Refractive Index of GaN, AlN and AlGaN Alloys

1999 ◽  
Vol 4 (S1) ◽  
pp. 502-507 ◽  
Author(s):  
J. F. Muth ◽  
J. D. Brown ◽  
M. A. L. Johnson ◽  
Zhonghai Yu ◽  
R. M. Kolbas ◽  
...  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Optoelectronic Devices ◽  
Optical Absorption Coefficient ◽  
Solar Blind ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Transmission Measurements ◽  
Reflectance Measurements

The design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AlN and AlGaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AlGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.

Absorption Coefficient and Refractive Index of GaN, AIN and AlGaN Alloys

1998 ◽  
Vol 537 ◽  
Author(s):  
J. F. Muth ◽  
J. D. Brown ◽  
M. A. L. Johnson ◽  
Zhonghai Yu ◽  
R. M. Kolbas ◽  
...  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Optoelectronic Devices ◽  
Optical Absorption Coefficient ◽  
Solar Blind ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Transmission Measurements ◽  
Reflectance Measurements

AbstractThe design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AIN and A1GaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AIGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.

Optical Properties of RF-Sputtered a-SiGe:H:O Alloys

1986 ◽  
Vol 77 ◽  
Author(s):  
J. M. T. Pereira ◽  
P. K. Banerjee ◽  
S. S. Mitra
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Constants ◽  
Rf Sputtering ◽  
Normal Incidence ◽  
Reflection And Transmission ◽  
Amorphous Thin Films ◽  
Optical Gap ◽  
Transmission Measurements ◽  
Substrate Temperatures

ABSTRACTAmorphous thin films of SixGe1-x:O (x = 0.70) were prepared by RF-sputtering at several substrate temperatures. The structural properties of these films were studied by IR spectroscopy and revealed features characteristic of hydrogen and/or oxygen bonded to silicon. The optical constants (n,k) were determined from reflection and transmission measurements at near-normal incidence for photon energies in the range of 1 eV and 2.6 eV. The optical gap was derived from the Taue plot and correlated with the composition of the samples. The increase of hydrogen and/or oxygen decreases the value of the refractive index and increases the optical gap.

Absolute Absorption Intensity and Dispersion Measurements on Some Organic Liquids in the Infrared

1980 ◽  
Vol 34 (6) ◽  
pp. 657-691 ◽  
Author(s):  
T. G. Goplen ◽  
D. G. Cameron ◽  
R. N. Jones
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Complex Refractive Index ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Organic Liquids ◽  
Absorption Coefficients ◽  
Absorption Intensity ◽  
Transmission Measurements ◽  
Infrared Absorption Spectra

The infrared absorption spectra and corresponding dispersion spectra of the following liquids have been measured over the range 4200 to 250 cm−1: cyclo-C5H10, CH3·NO2, CH3·CN, CH2Br2, CH2Cl2, CBrCl3, CCl4, C6H6, C6H5·CH3, C6H5Cl, C6H5Br, C6H5I, and C6F6. The spectra were measured in the absence of solvent and the results are reported as the real and imaginary components of the complex refractive index ( n, k). The experimental technique combines transmission measurements through thin films and attenuated total reflection measurements by a method which has been described previously. The complete spectral and dispersion curves are displayed graphically; the absorption maxima are tabulated as absorption indices ( kmax) and as molar absorption coefficients (εmax). The dispersion extrema ( nmin, nmax) are also listed and the experimental uncertainties in these quantities are evaluated. Provision is made to supply the complete optical constant data on magnetic tape at encoded intervals of 0.5 cm−1.

Effect of Overlapping Bands on Intensities in ATR FT-IR Spectra

1992 ◽  
Vol 46 (6) ◽  
pp. 1014-1019 ◽  
Author(s):  
J. B. Huang ◽  
M. W. Urban
Keyword(s):  
Refractive Index ◽  
Spectral Resolution ◽  
Spectral Features ◽  
Dispersion Effect ◽  
Ft Ir ◽  
Transmission Measurements ◽  
Refractive Index Spectrum ◽  
The Difference ◽  
Overlapping Region ◽  
Overlapping Bands

In this study, several spectra were simulated, and the effect of spectral resolution and intensity is compared for ATR and transmission measurements. The analysis of ATR spectra shows that the intensity differences become more pronounced with the increasing band intensities and decreasing separation of the bands. The intensity ratio differences in ATR spectra are due to the superposition of the asymmetric dispersion bands of the refractive index spectrum. The difference between the spectral features in an overlapping region in ATR and transmission measurements is illustrated, and it is shown that the optical dispersion effect can be effectively eliminated by converting an ATR spectrum into its absorbance counterpart with the use of the Kramers-Kronig transform.

Dependence of nonlinear refractive index of ZnSe on Be and Mg content

2010 ◽  
Vol 18 (4) ◽  
Author(s):  
B. Derkowska ◽  
F. Firszt ◽  
A. Marasek ◽  
B. Sahraoui
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Nonlinear Refractive Index ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Transmission Measurements ◽  
Two Photon Absorption Coefficient ◽  
Mg Content ◽  
532 Nm

AbstractThe values of the nonlinear refractive index n2 and the two-photon absorption coefficient β of ternary and quaternary ZnSe-based mixed crystals were extracted from the standard backward degenerate four wave mixing (DFWM) and nonlinear transmission measurements at 532 nm, respectively. Studied crystals were grown by the modified high-pressure Bridgman method. We found that the value of the nonlinear refractive index n2 for Zn0.79Be0.21Se is higher than that for Zn0.80Mg0.20Se. However, the opposite behaviour was found in the case of two-photon absorption coefficient β for these compounds. We also found that the values of the nonlinear refractive index n2 and the two-photon absorption coefficient β for Zn0.83Be0.04Mg0.13Se are about five times lower and three times higher than that for Zn0.80Mg0.13Se, respectively. In the case of ternary ZnSe-based crystals we noticed that the value of the nonlinear refractive index n2 decreases with increasing Mg or Be content. However, the value of the two-photon absorption coefficient β increases with increasing Mg or Be content.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

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