Dispersion de réfraction de l'argon, du krypton et du xénon sous les états solide et liquide

1970 ◽  
Vol 48 (17) ◽  
pp. 1947-1948 ◽  
Author(s):  
Jules Marcoux
Keyword(s):  
Visible Region ◽  
Index Of Refraction ◽  
Rare Gases ◽  
Solid States ◽  
Graph Form

Variations of the index of refraction, in the visible region, for three rare gases, argon, krypton, and xenon, in the liquid and solid states have been measured. The measured values are given in table and graph form. The value of n∞ for solid xenon is determined.

ABSORPTION OF LIGHT BY SMALL DROPS OF WATER

1943 ◽  
Vol 21a (10) ◽  
pp. 79-88 ◽  
Author(s):  
R. Ruedy
Keyword(s):  
Infrared Absorption ◽  
Extinction Coefficient ◽  
Unit Area ◽  
Visible Region ◽  
Index Of Refraction ◽  
Absorption Bands ◽  
Absorption Of Light ◽  
Gradual Approach ◽  
Infrared Absorption Bands ◽  
Initial Intensity

When the extinction coefficient k in the attenuation formula I/I0 = (exp) — kz for a beam of radiations of initial intensity I0, and intensity I after travelling a distance z in water, changes from about 10−4, the value measured in the visible region, to 103, the value reached in some infrared absorption bands for water in bulk, the coefficient of extinction for water in very small drops, calculated according to Mie's theory, increases as long as the wavelength used is larger than the radius a of the particle. With larger drops, that is, when the wave-lengths are shorter than the radius, the coefficient for the extinction by water particles with strong absorption is smaller than that for perfectly transparent particles. However, the change does not exceed about 10% even where the absorption is strongest, and it is negligible when wavelengths smaller than one micron are considered. The main features of the coefficient of extinction per unit area of the drop remain unchanged by absorption; first there is a rapid increase with decreasing wave-lengths for particles of a given diameter until the ratio a/λ = 1/n (the reciprocal of the index of refraction) is reached, then follows a more gradual approach to a maximum, slightly less than 4πa2 as 2a/λ increases to unity, and finally, when λ is quite small, a decrease towards a constant value after a small number of fluctuations that reach their greatest amplitudes near the integer multiples of 2a/λ.

Infrared Spectroscopy of Epitaxial Antimony Sulpho Iodide Thin Films

2001 ◽  
Vol 688 ◽  
Author(s):  
S. Kotru ◽  
S. Surthi ◽  
R. K. Pandey ◽  
D. Donnelly
Keyword(s):  
Thin Films ◽  
Infrared Detector ◽  
Visible Region ◽  
Pulsed Laser ◽  
Index Of Refraction ◽  
Laser Deposition ◽  
Silicon Substrates ◽  
Frequency Range ◽  
Oriented Film ◽  
Reflectance Measurements

AbstractThin films of antimony sulpho iodide (SbSI) were grown on platinized silicon substrates by the pulsed laser deposition method. As grown films were amorphous and annealing at 250 °C for 5 minutes introduced crystallinity in the films. Infrared reflectance measurements were done in the frequency range ∼ 500 – 5000 cm−1 (wavelength ∼ 2–20 μm). The reflectance measurements were taken at temperatures above and below the ferroelectric transition of SbSI ∼ 20° C. The index of refraction for a (121) oriented film was determined to be 2.83 ± 0.35 at a temperature of 25.6 °C, and 2.80 ± 0.35 at a temperature of 9.6 °C. For a (002) oriented film, the index was 3.82 ± 0.48 at a temperature of 26.5 °C, and 3.76 ± 0.48 at a temperature of 8.0 °C. Pyro-optic coefficients of 1.5 × 10−3 °C−1 for the (121) oriented film, and 3.2 × 10−3 °C−1 for the (002) oriented film were obtained. These results are consistent with measurements done in the visible region, and demonstrate the potential of SbSI as an infrared detector material.

Point Focus Solar Spectral Splitting System for CPV Applications

2013 ◽  
Vol 1493 ◽  
pp. 65-69
Author(s):  
Ahmed Zayan ◽  
Matteo Chiesa ◽  
Marco Stefancich
Keyword(s):  
Visible Region ◽  
Optical Element ◽  
Ambient Air ◽  
Merit Function ◽  
Index Of Refraction ◽  
Mathematical Framework ◽  
Angle Of Incidence ◽  
Prismatic Structure ◽  
Current Matching ◽  
Spectral Splitting

ABSTRACTSolar spectral splitting technologies have been investigated over the years as alternatives to improve the efficiencies obtained from photovoltaic devices by splitting the incident solar light into its respective wavelengths, and aligning a series of photovoltaic cells arranged next to each other as opposed to being physically stacked on top of each other as is the case with multijunction cells. Limitations previously posed by multijunction cells like current matching and lattice matching are circumvented through this approach, allowing for a broader and potentially cheaper pool of candidate cells to be used for energy conversion. In this study, we design and gauge the performance of a single optical element capable of splitting the light and concentrating it simultaneously unto a bed of photovoltaics, each illuminated by the part of the spectrum that corresponds best to its relevant properties such as the bandgap and the external quantum efficiency. The prismatic structure constituting the device relies on the device’s transmission in the visible region and its dispersion. Presented in this study is the mathematical framework used in designing the structure for a specific merit function; in particular, the study focuses on minimizing optical losses at the interfaces of the structure with the ambient air. Variables like the index of refraction of the material used, the angle of incidence on the surface, the exit angle of the light out of the structure factor into the optical center’s design. Compared to alternative splitting technologies like dichroic mirrors, the model splits the incident polychromatic light into a continuous band of wavelengths as opposed to discrete wavelengths that can be adapted on to different sets of single junction cells. The device is an improvement to our published 1-axis linear concentrator reported earlier in the year for its point-focus output yielding in even higher concentration and potentially lowers costs.

The observation of nano-voids in Au thin films

1987 ◽  
Vol 45 ◽  
pp. 366-367
Author(s):  
William Krakow
Keyword(s):  
Thin Films ◽  
Melting Point ◽  
Present Author ◽  
Stacking Faults ◽  
Damage Threshold ◽  
Ionic Species ◽  
Rare Gases ◽  
Chain Defects ◽  
Vacancy Chains ◽  
Au Thin Films

It has long been known that defects such as stacking faults and voids can be quenched from various alloyed metals heated to near their melting point. Today it is common practice to irradiate samples with various ionic species of rare gases which also form voids containing solidified phases of the same atomic species, e.g. ref. 3. Equivalently, electron irradiation has been used to produce damage events, e.g. ref. 4. Generally all of the above mentioned studies have relied on diffraction contrast to observe the defects produced down to a dimension of perhaps 10 to 20Å. Also all these studies have used ions or electrons which exceeded the damage threshold for knockon events. In the case of higher resolution studies the present author has identified vacancy and interstitial type chain defects in ion irradiated Si and was able to identify both di-interstitial and di-vacancy chains running through the foil.

Interferometric (Fourier-Spectroscopic) Measurement of Electron Energy Distributions

1990 ◽  
Vol 48 (2) ◽  
pp. 110-111 ◽  
Author(s):  
F. Hasselbach ◽  
A. Schäfer
Keyword(s):  
Group Velocity ◽  
Wave Packets ◽  
Index Of Refraction ◽  
Electron Wave ◽  
Fringe Contrast ◽  
Faraday Cage ◽  
Optical Index ◽  
Wien Filter ◽  
Coherent Wave ◽  
Electric And Magnetic Fields

Möllenstedt and Wohland proposed in 1980 two methods for measuring the coherence lengths of electron wave packets interferometrically by observing interference fringe contrast in dependence on the longitudinal shift of the wave packets. In both cases an electron beam is split by an electron optical biprism into two coherent wave packets, and subsequently both packets travel part of their way to the interference plane in regions of different electric potential, either in a Faraday cage (Fig. 1a) or in a Wien filter (crossed electric and magnetic fields, Fig. 1b). In the Faraday cage the phase and group velocity of the upper beam (Fig.1a) is retarded or accelerated according to the cage potential. In the Wien filter the group velocity of both beams varies with its excitation while the phase velocity remains unchanged. The phase of the electron wave is not affected at all in the compensated state of the Wien filter since the electron optical index of refraction in this state equals 1 inside and outside of the Wien filter.

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.

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

CALCULATION OF THE FREE-BOUND CONTINUUM OF RARE GASES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-93-C7-94
Author(s):  
P. Ranson ◽  
J. Chapelle
Keyword(s):  
Rare Gases
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