A METHOD FOR THE DETERMINATION OF THE INDEX OF REFRACTION OF THIN TRANSPARENT FILMS

1948 ◽  
Vol 26a (4) ◽  
pp. 230-235 ◽  
Author(s):  
R. W. Stewart
Keyword(s):  
Thin Films ◽  
High Frequency ◽  
Air Gap ◽  
Index Of Refraction ◽  
Transparent Films ◽  
High Frequency Discharge ◽  
Discharge Tubes ◽  
Set Up ◽  
Fringe System

The index of refraction of thin films deposited on an optical flat is obtained by comparison of the fringe system set up in the film with that in the air gap between the film and another optical flat. The use of the method is illustrated by application to films produced in high frequency discharge tubes. Films produced in Pyrex glass and quartz tubes are shown to be silica in the form of cristobalite. Films produced in polystyrene tubes prove to have an index of refraction that is very low and is a function of the thickness.

scholarly journals Calculation improvement of no-load stray losses in induction motors with experimental validation

2015 ◽  
Vol 12 (3) ◽  
pp. 303-320
Author(s):  
Miloje Kostic
Keyword(s):  
High Frequency ◽  
Experimental Validation ◽  
Air Gap ◽  
New Classification ◽  
Iron Losses ◽  
Surface Iron ◽  
Space Harmonics ◽  
Rotor Cage

On the basis of the known fact that all air gap main flux density variations are enclosed by permeance slot harmonics, only one component of stray losses in rotor (stator) iron is considered in the new classification, instead of 2 components: rotor (stator) pulsation iron losses, and rotor (stator) surface iron losses. No-load rotor cage (high-frequency) stray losses are usually calculated. No-load stray losses are caused by the existence of space harmonics: the air-gap slot permeance harmonics and the harmonics produced by no-load MMF harmonics. The second result is the proof that the corresponding components of stray losses can be calculated separately for the mentioned kind of harmonics. Determination of the depth of flux penetration and calculations of high frequency iron losses are improved. On the basis of experimental validation, it is proved that the new classification of no-load stray losses and the proposed method for the calculation of the total value is sufficiently accurate.

On the application of a single-crystal κ-diffractometer and a CCD area detector for studies of thin films

2013 ◽  
Vol 20 (4) ◽  
pp. 644-647 ◽  
Author(s):  
Henrik Hovde Sønsteby ◽  
Dmitry Chernyshov ◽  
Michael Getz ◽  
Ola Nilsen ◽  
Helmer Fjellvåg
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Crystal Orientation ◽  
Atomic Layer ◽  
Area Detector ◽  
Layer Deposition ◽  
Crucial Information ◽  
Key Features ◽  
Set Up

A multipurpose six-axis κ-diffractometer, together with the brilliance of the ESRF light source and a CCD area detector, has been explored for studying epitaxial relations and crystallinity in thin film systems. The geometrical flexibility of the six-axis goniometer allows measurement of a large volume in reciprocal space, providing an in-depth understanding of sample crystal relationships. By a set of examples of LaAlO3thin films deposited by the atomic layer deposition technique, the possibilities of the set-up are presented. A fast panoramic scan provides determination of the crystal orientation matrices, prior to more thorough inspection of single Bragg nodes. Such information, in addition to a broadening analysis of families of single reflections, is shown to correlate well with the crystallinity, crystallite size, strain and epitaxial relationships in the thin films. The proposed set-up offers fast and easy sample mounting and alignment, along with crucial information on key features of the thin film structures.

A Method for Calculating the Index of Refraction of Thin Films

1975 ◽  
Vol 53 (18) ◽  
pp. 1737-1742 ◽  
Author(s):  
J. H. Wohlgemuth ◽  
D. E. Brodie
Keyword(s):  
Thin Films ◽  
Spectral Range ◽  
Variational Approach ◽  
Accurate Determination ◽  
Normal Incidence ◽  
Index Of Refraction ◽  
New Method ◽  
Reflection And Transmission ◽  
Transmission Measurements

A new method for determining the index of refraction from normal incidence reflection and transmission measurements has been developed. Several other methods are reviewed to explain why a new method is needed. The author's method used a thickness variational approach. For an accurate determination of n and k, the method requires normal incidence reflection and transmission measurements over a fairly broad spectral range for at least two different film thicknesses. These requirements are unavoidable for normal incidence methods.

scholarly journals Characterisation of dielectric 3D-printingmaterials at microwave frequencies

ACTA IMEKO ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 26
Author(s):  
Andrea Alimenti ◽  
Kostiantyn Torokhtii ◽  
Nicola Pompeo ◽  
Emanuele Piuzzi ◽  
Enrico Silva
Keyword(s):  
Quality Factor ◽  
Loss Tangent ◽  
Complex Permittivity ◽  
High Frequency ◽  
Measurement Method ◽  
Air Gap ◽  
3D Printer ◽  
Reliable Determination ◽  
Microwave Frequencies

<p class="Abstract">3D-printer materials are becoming increasingly appealing, especially for high frequency applications. As such, the electromagnetic characterisation of these materials is an important step in evaluating their applicability for new technological devices. We present a measurement method for complex permittivity evaluation based on a dielectric loaded resonator (DR). Comparing the quality factor <em>Q</em> of the DR with a disk-shaped sample placed on a DR base, with <em>Q</em> obtained when the sample is substituted with an air gap, allows a reliable determination of the loss tangent.</p>

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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