Measurement of the diameter and refractive index of fiber lightguides according to the number of refraction-interference fringes in the forward hemisphere

1990 ◽  
Vol 33 (12) ◽  
pp. 1213-1214
Author(s):  
A. B. Androsik
Keyword(s):  
Refractive Index ◽  
Interference Fringes ◽  
Fiber Lightguides ◽  
Forward Hemisphere

Optic Method to Measure the Density of Gas and the Analysis on Uncertainty of Measurement

2011 ◽  
Vol 361-363 ◽  
pp. 226-231
Author(s):  
Chang Li Guo ◽  
Yan Qing Zhang
Keyword(s):  
Refractive Index ◽  
Measurement Accuracy ◽  
Uncertainty Of Measurement ◽  
Interference Theory ◽  
Interference Fringes ◽  
Air Chamber ◽  
High Measurement ◽  
Wedge Structure ◽  
High Measurement Accuracy ◽  
Optical Wedge

A optic method to measure the density of gas is put forward. That is, by using the optical Wedge structure to build air chamber and chamber for gas under test, and by measuring the differences of the optical Wedge interference fringes of the two rooms, the density of gas has been measured. The interference theory of Wedge has been theoretical analyzed, and a formula which can be used to measure the refractive index of gas is put forward, and the uncertainty of the measurement has been analyzed. The parameters of gas density, refractive index and gas thickness have been used in the formula. The results show that the method of optical Wedge interference is practical, and high measurement accuracy is achievement when the density of gas is high.

scholarly journals AlGaN-Based Bragg Reflectors

1997 ◽  
Vol 2 ◽  
Author(s):  
O. Ambacher ◽  
M. Arzberger ◽  
D. Brunner ◽  
H. Angerer ◽  
F. Freudenberg ◽  
...  
Keyword(s):  
Refractive Index ◽  
Molecular Beam ◽  
Molar Fraction ◽  
Bragg Reflectors ◽  
Near Ultraviolet ◽  
Photothermal Deflection Spectroscopy ◽  
Interference Fringes ◽  
Measured Absorption ◽  
Ultraviolet Spectral Region ◽  
Photothermal Deflection

We have studied the dependence of the absorption edge and the refractive index of wurtzite AlxGa1−xN films on composition using transmission, ellipsometry and photothermal deflection spectroscopy. The Al molar fraction of the AlxGa1−xN films grown by plasma-induced molecular beam epitaxy was varied through the entire range of composition (0 ≤ x ≤ 1). We determined the absorption edges of AlxGa1−xN films and a bowing parameter of 1.3 ± 0.2 eV. The refractive index below the bandgap was deduced from the interference fringes, the dielectric function between 2.5 and 25 eV from ellipsometry measurements. The measured absorption coefficients and refractive indices were used to calculate the design and reflectivity of AlGaN-based Bragg reflectors working in the blue and near-ultraviolet spectral region.

Optical Constants of Annealed a-Si:H from Transmittance at Normal Incidence

2001 ◽  
Vol 692 ◽  
Author(s):  
Atsutoshi Doi ◽  
Yoshiyuki Matsumoto
Keyword(s):  
Refractive Index ◽  
Network Structure ◽  
Optical Constants ◽  
Solid Phase ◽  
Refractive Index Change ◽  
Normal Incidence ◽  
Solid Phase Crystallization ◽  
Index Change ◽  
Temperature Changes ◽  
Interference Fringes

AbstractWe study changes in the optical constants of a-Si:H films caused by the thermal annealing involved in solid phase crystallization. The aim is to examine the growth mechanism, since changes in refractive index are most probably caused by a change in the network structure. The refractive index change was studied from interference fringes in transmitted light at normal incidence, and shows differing dependence on temperature in different thermal ranges. DSC measurement was also performed to examine changes in the network structure with temperature. Changes in optical and thermal properties induced by an increase of temperature reveal frequent network changes of a-Si:H below 470°C and of a-Si in the range 470 to 570°C. We also found crystallization at about 570°C, and grain growth above the crystallization temperature. Knowledge of network changes in a-Si film allows orientation control by an external seed.

Three-dimensional refractive index profile of a GRIN optical waveguide using multiple beam interference fringes

2001 ◽  
Vol 191 (1-2) ◽  
pp. 39-47 ◽  
Author(s):  
N. Barakat ◽  
H.A. El-Hennawi ◽  
E.Abd. El-Ghafar ◽  
H. El-Ghandoor ◽  
R. Hassan ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Waveguide ◽  
Three Dimensional ◽  
Refractive Index Profile ◽  
Index Profile ◽  
Multiple Beam ◽  
Interference Fringes

Thickness and refractive index measurements using multiple beam interference fringes (FECO)

2003 ◽  
Vol 264 (2) ◽  
pp. 548-553 ◽  
Author(s):  
Rafael Tadmor ◽  
Nianhuan Chen ◽  
Jacob N. Israelachvili
Keyword(s):  
Refractive Index ◽  
Multiple Beam ◽  
Interference Fringes

Determination of the Complex Refractive Index of Materials via Infrared Measurements

2002 ◽  
Vol 56 (8) ◽  
pp. 1107-1113 ◽  
Author(s):  
Christos-Platon E. Varsamis
Keyword(s):  
Refractive Index ◽  
Dielectric Function ◽  
Complex Refractive Index ◽  
Infrared Reflectance ◽  
Finite Samples ◽  
Interference Fringes ◽  
Infrared Measurements ◽  
Optical Effects ◽  
Si Wafer

In this work, methods are presented for obtaining the real, n, and imaginary, k, parts of the complex refractive index of materials considered as semi-infinite and finite from infrared reflectance, R( ν), and/or transmittance, T( ν), spectra. In semi-infinite samples, with negligible T( ν), only R( ν) is measured, and n and k can derive from the Kramers–Kronig (K–K) transformation or the modeling of the dielectric function of the material. In finite samples, the interference fringes due to multiple internal reflections can significantly alter the measured spectra. It was demonstrated that whenever the period of the fringes is on the order of a few cm−1, n and k can be equivalently obtained by the extended K–K analysis for T( ν) spectra, the modeling of the dielectric function, and the inversion of low-resolution R( ν) and T( ν) spectra, as well as the acquisition of a single high-resolution R( ν) or T( ν) spectrum. Otherwise, n and k can be calculated by modeling the dielectric function of the material once the optical effects are carefully removed. These methods were applied in infrared measurements of crystalline Si wafer and of glassy 0.20AgI·0.80[Ag2O·2B2O3].

Optical Constant Determination of Thin Polymer Films in the Infrared

1985 ◽  
Vol 39 (3) ◽  
pp. 405-408 ◽  
Author(s):  
R. T. Graf ◽  
J. L. Koenig ◽  
H. Ishida
Keyword(s):  
Refractive Index ◽  
Optical Constant ◽  
Infrared Region ◽  
Transmission Spectra ◽  
Thin Polymer Films ◽  
Interference Fringes ◽  
Constant Determination ◽  
Thin Polymer ◽  
Good Agreement

Thin films of poly(vinyl chloride), poly(methyl methacrylate), and poly(styrene) were analyzed by Fourier transform infrared spectroscopy. The interference fringes present in the transmission spectra of these samples were used to determine film thickness and average refractive index. Subsequent Kramers-Kronig analysis of these transmission spectra provided the dispersion of the refractive index and the absorption index across the entire mid-infrared region. Interference fringes were absent in the optical constant spectra, and good agreement was obtained between our optical constant spectra and those of other authors.

Removing interference-based effects from infrared spectra – interference fringes re-revisited

The Analyst ◽  
2020 ◽  
Vol 145 (9) ◽  
pp. 3385-3394 ◽  
Author(s):  
Thomas G. Mayerhöfer ◽  
Susanne Pahlow ◽  
Uwe Hübner ◽  
Jürgen Popp
Keyword(s):  
Refractive Index ◽  
Infrared Spectra ◽  
Band Intensity ◽  
Interference Fringes ◽  
Spectrum Interpretation

Substantial refractive index mismatches between substrate and layers lead to undulating baselines and changes of band intensity, shape and position. For proper spectrum interpretation, all of these effects must be removed.

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