The use of a slit in determining refractive indices with the microscope

1917 ◽  
Vol 18 (84) ◽  
pp. 130-132
Author(s):  
John William Evans
Keyword(s):  
Crystal Structure ◽  
Refractive Index ◽  
Optical Properties ◽  
Critical Angle ◽  
Total Reflection ◽  
Index Of Refraction ◽  
Refractive Indices ◽  
Object Image ◽  
Ordinary Object

Certain optical properties of crystals, and more particularly the refractive index, may be determined either in the directions-image, often referred to as the 'image in convergent light', or in the ordinary object-image in which the object itself is seen. In the former case, in which the index of refraction is 'usually determined by means of the critical angle of total-reflection, every point in the image corresponds to a single direction of propagation of the wave-front through the crystal-structure and to the two corresponding directions of vibration. One of these can, however, be eliminated by the insertion of a nicol in an approximate position, and thus all ambiguity in the determination of the refractive index is removed.

A diagram for use with the total-reflectometer

1912 ◽  
Vol 16 (75) ◽  
pp. 236-238 ◽  
Author(s):  
A. Hutchinson
Keyword(s):  
Refractive Index ◽  
Critical Angle ◽  
Graphical Method ◽  
Plane Surface ◽  
Monochromatic Light ◽  
Total Reflection ◽  
Plate Viii

The accompanying diagram (Plate VIII) has been prepared in order to facilitate the determination of indices of refraction with the Kohlrausch total-reflectometer, by affording a means of rapidly werking out the results by a graphical method.The Kohlrausch instrument enables measurements to be made of the critical angle θ, at which total reflection begins, when monochromatic light is reflected at the plane surface of a solid of refractive index μ immersed in a liquid of higher refractive index μ′.

On the influence of the thickness of air-space on total reflection of electric radiation

1898 ◽  
Vol 62 (379-387) ◽  
pp. 300-310 ◽  
Keyword(s):  
Critical Angle ◽  
Total Reflection ◽  
Index Of Refraction ◽  
Angle Of Incidence ◽  
Minimum Thickness ◽  
Light Waves ◽  
Air Space ◽  
Air Film ◽  
The Given

In my preliminary experiments on the determination of the index of refraction of various substances for electric radiation, I used a single serai-cylinder of the given substance; the electric ray was refracted from the denser medium into air, and at the critical angle of incidence it underwent total reflection. The experiment was repeated with two semi-cylinders separated by a parallel air-space. With light waves an extremely thin air-film is effective in producing total reflection. But a question might arise whether waves a hundred thousand times as long would be totally reflected by films of air, and, if so, it would be interesting to find out the minimum thickness of air-space which would be effective in producing this result.

scholarly journals On the determination of the indices of refraction of various substances for the electric ray. II. Index of refraction of glass

1898 ◽  
Vol 62 (379-387) ◽  
pp. 293-300 ◽  
Keyword(s):  
Royal Society ◽  
Critical Angle ◽  
Total Reflection ◽  
Index Of Refraction ◽  
Angle Of Incidence ◽  
Air Space ◽  
The Given

In my previous paper, read before the Royal Society on October 20, 1895, I described a method of determining the indices of refraction of various substances for electric radiation, the principle of which depends on the determination of the critical angle at which total reflection takes place. A semi-cylinder of the given substance was taken, and the angle of incidence gradually increased till the rays were totally reflected. The experiment was repeated with two semi-cylinders, separated by a parallel air-space.

scholarly journals Optical properties of D-serine doped TGS crystals for pyroelectric sensors

2015 ◽  
Vol 33 (4) ◽  
pp. 692-698
Author(s):  
V.Yu. Kurlyak ◽  
V.Yo. Stadnyk ◽  
B.V. Andriyevsky ◽  
M.O. Romanyuk ◽  
Z.O. Kohut ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Density Functional ◽  
Reference Data ◽  
Refractive Indices ◽  
Proper Position ◽  
Functional Theory ◽  
Pyroelectric Sensors ◽  
Materials Used

AbstractRefractive and birefringence indices in the range of transparency of 300 to 700 nm for triglycine sulphate crystals doped with D-serine molecules have been measured in the temperature range of 290 K to 340 K. The obtained optical properties are discussed together with characteristic electrical features of these materials used as pyroelectric sensors for measurement of temperature. The experimental results obtained in this study will be necessary as the reference data for comparison with the calculated refractive indices of TGS + D-serine on the basis of density functional theory. Determination of the proper position of D-serine, will reveal the features of TGS + D-serine crystal structure necessary to achieve stable unipolarity.

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

scholarly journals Refractive index evaluation of porous silicon using Bragg reflectors

2018 ◽  
Vol 64 (1) ◽  
pp. 72 ◽  
Author(s):  
D. Estrada-Wiese ◽  
J.A. Del Río
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Simple Procedure ◽  
Merit Function ◽  
Refractive Indices ◽  
Bragg Reflectors ◽  
Photonic Bandgaps ◽  
Photonic Structures ◽  
Index Evaluation

There are two main physical properties needed to fabricate 1D photonic structures and form perfect photonic bandgaps: the quality of thethickness periodicity and the refractive index of their components. Porous silicon (PS) is a nano-structured material widely used to prepare 1Dphotonic crystals due to the ease of tuning its porosity and its refractive index by changing the fabrication conditions. Since the morphologyof PS changes with porosity, the determination of PS’s refractive index is no easy task. To find the optical properties of PS we can usedifferent effective medium approximations (EMA). In this work we propose a method to evaluate the performance of the refractive index ofPS layers to build photonic Bragg reflectors. Through a quality factor we measure the agreement between theory and experiment and thereinpropose a simple procedure to determine the usability of the refractive indices. We test the obtained refractive indices in more complicatedstructures, such as a broadband Vis-NIR mirror, and by means of a Merit function we find a good agreement between theory and experiment.With this study we have proposed quantitative parameters to evaluate the refractive index for PS Bragg reflectors. This procedure could havean impact on the design and fabrication of 1D photonic structures for different applications.

Optical properties of a liquid crystal with small ordinary and extraordinary refractive indices and small optical anisotropy

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Kędzierski ◽  
K. Garbat ◽  
Z. Raszewski ◽  
M. Kojdecki ◽  
K. Kowiorski ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Optical Anisotropy ◽  
Order Parameter ◽  
Orientational Order ◽  
Refractive Indices ◽  
Orientational Order Parameter ◽  
Unknown Density ◽  
Abbe Refractometer

AbstractOptical properties of a nematic liquid crystal with small refractive index and small birefringence were studied. The ordinary and extraordinary refractive indices and birefringence were measured as functions of temperature by using an Abbe refractometer and wedge nematic cells. From values of these indices the nematic orientational order parameter was calculated by using several methods and corresponding mathematical models. Kuczyński et al. method was found to be suitable for determining the order parameter also for materials featuring small ordinary refractive index, with unknown density.

Refractive index measurements and order parameter determination of the liquid crystal p-ethoxybenzilidene-p-n-butylaniline

1981 ◽  
Vol 59 (4) ◽  
pp. 515-520 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. A. Balzarini
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Order Parameter ◽  
Orientational Order ◽  
Parameter Determination ◽  
Refractive Indices ◽  
Temperature Changes ◽  
Interferometric Technique ◽  
Anisotropic Fluids

Using a simple new interferometric technique, the ordinary and extraordinary refractive indices of the nematic liquid crystal p-ethoxybenzilidene-p-n-butylaniline have been measured separately as a function of temperature. Changes in the refractive indices have been measured with an accuracy of ±0.005% and the absolute values with an accuracy of ±0.5%. Thermal expansivity data has been obtained by utilizing a specially constructed thermometer containing the sample. By using a recently developed Clausius–Mossotti relation for anisotropic fluids, the effective molecular polarizability and hence the orientational order parameter have been obtained from refractive index and density measurements as a function of temperature.

Optical Properties of AlGaAsSb, AlGalnP, AlGaInAs, and GaInAsP for Optoelectronic Applications

1999 ◽  
Vol 579 ◽  
Author(s):  
M. Linnik ◽  
A. Christou
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Interband Transition ◽  
Theoretical Data ◽  
Quaternary Alloy ◽  
Refractive Indices ◽  
Incident Wavelength ◽  
Semiconductor Alloy ◽  
Transparent Region ◽  
Semi Empirical

ABSTRACTThe authors present calculations of quaternary III–V semiconductor alloy optical properties and the comparison of the theoretical data with available experimental results for AlGaAsSb, AlGaInP, AlGaInAs, and GaInAsP alloys. The investigation includes material's energy bandgap and refractive index calculations as a function of the incident wavelength in the transparent region, as well as the composition of the alloy. Optimization of the quaternary alloy refractive indices was obtained from a semi-empirical dielectric function calculations based on the interband transition contributions.

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