Experimental Verification of Two-Beam method to Determine the Refractive Index of Liquids

2005 ◽  
Vol 34 (4) ◽  
pp. 193-197
Author(s):  
Shyam Singh
Keyword(s):  
Refractive Index ◽  
Experimental Verification ◽  
Beam Method

scholarly journals THE VISIBILITY OF MONOCHROMATIC RADIATION AND THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1922 ◽  
Vol 5 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Selig Hecht ◽  
Robert E. Williams
Keyword(s):  
Refractive Index ◽  
Absorption Spectrum ◽  
Absorption Coefficient ◽  
Experimental Verification ◽  
High Intensity ◽  
Absorption Maximum ◽  
Water Solution ◽  
Wave Length ◽  
Relative Energy ◽  
Existing Data

1. After a consideration of the existing data and of the sources of error involved, an arrangement of apparatus, free from these errors, is described for measuring the relative energy necessary in different portions of the spectrum in order to produce a colorless sensation in the eye. 2. Following certain reasoning, it is shown that the reciprocal of this relative energy at any wave-length is proportional to the absorption coefficient of a sensitive substance in the eye. The absorption spectrum of this substance is then mapped out. 3. The curve representing the visibility of the spectrum at very low intensities has exactly the same shape as that for the visibility at high intensities involving color vision. The only difference between them is their position in the spectrum, that at high intensities being 48 µµ farther toward the red. 4. The possibility is considered that the sensitive substances responsible for the two visibility curves are identical, and reasons are developed for the failure to demonstrate optically the presence of a colored substance in the cones. The shift of the high intensity visibility curve toward the red is explained in terms of Kundt's rule for the progressive shift of the absorption maximum of a substance in solvents of increasing refractive index and density. 5. Assuming Kundt's rule, it is deduced that the absorption spectrum of visual purple as measured directly in water solution should not coincide with its position in the rods, because of the greater density and refractive index of the rods. It is then shown that, measured by the position of the visibility curve at low intensities, this shift toward the red actually occurs, and is about 7 or 8 µµ in extent. Examination of the older data consistently confirms this difference of position between the curves representing visibility at low intensities and those representing the absorption spectrum of visual purple in water solution. 6. It is therefore held as a possible hypothesis, capable of direct, experimental verification, that the same substance—visual purple—whose absorption maximum in water solution is at 503 µµ, is dissolved in the rods where its absorption maximum is at 511 µµ, and in the cones where its maximum is at 554 µµ (or at 540 µµ, if macular absorption is taken into account, as indeed it must be).

An optical study of turbulence

1970 ◽  
Vol 43 (3) ◽  
pp. 607-635 ◽  
Author(s):  
G. E. Roe
Keyword(s):  
Refractive Index ◽  
Power Spectrum ◽  
Power Spectra ◽  
Mean Flow ◽  
Cavendish Laboratory ◽  
Turbulent Region ◽  
Single Beam ◽  
Beam Method ◽  
A New Technique ◽  
Spatial Power Spectrum

This paper describes theoretical and experimental work carried out at the Cavendish Laboratory of the University of Cambridge. The main object of the work was to develop a new technique for measuring the structure of fluid turbulence.A parallel beam of light is passed through the turbulent region, containing refractive index fluctuations, and analyzed on exit by gratings of periodic transmissivity. Two forms of analysis yield (a) the spatial power spectrum of the refractive index fluctuations in the turbulence, and (b) the velocity distribution within the beam aperture. The method does not disturb the fluid physically, does not depend on the existence of a mean flow velocity, and works well in liquids.One of the limitations of this single-beam method is that it produces information averaged along the path length of the beam in the turbulence, and to overcome this a cross-beam technique, using two beams intersecting at right-angles, has been developed in theory. This method gives the spatial power spectrum of the refractive index fluctuations, as does the single beam method, but the results are characteristic only of the volume of intersection of the beams.The paper first discusses the theory of the single-beam and crossed-beam techniques, and then experimental results obtained with the single-beam method.The turbulent region investigated was a rectangular tank of water, heated from below and cooled from above, producing convective turbulence of high Rayleigh number (4·1 × 108), a system difficult to analyze by conventional methods of measurement, such as the hot-wire anemometer.Spectral density functions (power spectra) of refractive index, and hence in this case temperature fluctuations, have been measured, as have velocity distributions. Statistical analysis of the results also gives useful information about the Eulerian time scale of the turbulent field.

Fea-Based Modeling for High Refractive Index Optical Nanocomposites With Experimental Verification

2021 ◽  
Author(s):  
Sipan Liu ◽  
Darryl Boyd ◽  
Md Didarul Islam ◽  
Yeongun Ko ◽  
Woohong (Rick) Kim ◽  
...  
Keyword(s):  
Refractive Index ◽  
Experimental Verification ◽  
High Refractive Index
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