scholarly journals Passive Measurements of the Refractive Index of Liquid Nitrogen and Free-flowing substances by the Prism Method in the Millimeter Wavelength Range

2021 ◽  
Vol 13 (4) ◽  
pp. 435-443
Author(s):  
Valery A. Golunov ◽  
◽  
Konstantin V. Gordeev ◽  
Konstantin N. Rykov ◽  
◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Nitrogen ◽  
Wavelength Range ◽  
Black Body ◽  
Test Substance ◽  
Particle Sizes ◽  
Radiation Mode ◽  
Millimeter Wavelength ◽  
Lens Antennas ◽  
Passive Measurements

It is proposed to use the classical prism method in the millimeter wavelength range for measuring the refractive index of liquid and free-flowing substances, including mixtures with particle sizes comparable to the wavelength. The method is implemented using a hollow radio transparent rectangular prism filled with a test substance. The measurements were carried out in the thermal radiation mode using radiometers with horn-lens antennas at frequencies of 37.5 and 94 GHz. To measure the deflection of the refracted beam, a linear scanner with a black body mounted on it, cooled with liquid nitrogen, was used. The distance between the prism and the scanner was 1 m. The refractive index of liquid nitrogen, sand, gravel, marble chips and granular polyethylene were measured. Using the refractive formula and the Landau-Lifshitz-Looeng formula for calculating the dependence of the refractive index of binary mixtures on the bulk density of particles, estimates of the refractive index of the material of the particles that make up the substances under study are obtained. They are in satisfactory agreement with the known experimental data for quartz, feldspar, granite, and marble.

scholarly journals ELECTRODELESS MEASUREMENT TECHNIQUE OF COMPLEX DIELECTRIC PERMITTIVITY OF HIGH-K DIELECTRIC FILMS IN THE MILLIMETER WAVELENGTH RANGE

2016 ◽  
Vol 52 ◽  
pp. 161-167 ◽  
Author(s):  
Igor V. Kotelnikov ◽  
Andrey G. Altynnikov ◽  
Anatoly Konstantinovich Mikhailov ◽  
Valentina V. Medvedeva ◽  
Andrey Kozyrev
Keyword(s):  
Dielectric Permittivity ◽  
Wavelength Range ◽  
Measurement Technique ◽  
Complex Dielectric Permittivity ◽  
Dielectric Films ◽  
Millimeter Wavelength ◽  
High K ◽  
High K Dielectric

scholarly journals Optical, microphysical and compositional properties of the Eyjafjallajökull volcanic ash

2014 ◽  
Vol 14 (9) ◽  
pp. 13271-13300 ◽  
Author(s):  
A. Rocha-Lima ◽  
J. V. Martins ◽  
L. A. Remer ◽  
N. A. Krotkov ◽  
M. H. Tabacniks ◽  
...  
Keyword(s):  
Refractive Index ◽  
Volcanic Ash ◽  
Fine Particles ◽  
Absorption Efficiency ◽  
Particle Sizes ◽  
Air Volume ◽  
Automatic Software ◽  
Compositional Properties ◽  
Size Distribution Of Particles ◽  
Mass Absorption Efficiency

Abstract. Microphysical, optical, and compositional properties of the volcanic ash from the April–May (2010) Eyjafjallajökull volcanic eruption are presented. Samples of the volcanic ash were taken on the ground in the vicinity of the volcano. The material was sieved, re-suspended, and collected on filters, separating particle sizes into coarse and fine modes. The spectral mass absorption efficiency αabs [m2 g−1] was determined for coarse and fine particles in the wavelength range from 300 to 2500 nm. Size distribution of particles on filters was obtained using a semi-automatic software to analyze images obtained by Scanning Electron Microscopy (SEM). The grain density of the volcanic ash was determined as 2.16(13) g cm−3 by measuring the variation of air volume in a system with volcanic ash and air under compression. Using Mie–Lorenz and T-matrix theories, the imaginary part of the refractive index was derived. Results show the spectral imaginary refractive index ranging from 0.001 to 0.005. Fine and coarse particles were analyzed by X-Ray fluorescence for elemental composition. Fine and coarse mode particles exhibit distinct compositional and optical differences.

scholarly journals Scattering and Absorption Cross-sections of Atmospheric Gases in the Ultraviolet-Visible Wavelength Range (307–725 nm)

2020 ◽  
Author(s):  
Quanfu He ◽  
Zheng Fang ◽  
Ofir Shoshamin ◽  
Steven S. Brown ◽  
Yinon Rudich
Keyword(s):  
Refractive Index ◽  
Wavelength Range ◽  
Cross Sections ◽  
Rayleigh Scattering ◽  
Dispersion Relations ◽  
Optical Absorption Spectroscopy ◽  
Absorption Cross ◽  
Atmospheric Gases ◽  
Scattering Cross ◽  
Scattering Cross Sections

Abstract. Accurate Rayleigh scattering and absorption cross-sections of atmospheric gases are essential for understanding the propagation of electromagnetic radiation in planetary atmospheres. Accurate extinction cross-sections are also essential for calibrating high finesse optical cavities and differential optical absorption spectroscopy and for accurate remote sensing. In this study, we measured the scattering and absorption cross-sections of carbon dioxide, nitrous oxide, sulfur hexafluoride, oxygen, and methane in the continuous wavelength range of 307–725 nm using Broadband Cavity Enhanced Spectroscopy (BBCES). The experimentally derived Rayleigh scattering cross-sections for CO2, N2O, SF6, O2, and CH4 agree with refractive index-based calculations, with a difference of 1.5 % and 1.1 %, 1.5 %, 2.9 %, and 1.4 % on average, respectively. The O2-O2 collision-induced absorption and absorption by methane are obtained with high precision at the 0.8 nm resolution of our BBCES instrument in the 307–725 nm wavelength range. New dispersion relations for N2O, SF6, and CH4 were derived using data in the UV-vis wavelength range. This study provides improved refractive index dispersion relations, n-based Rayleigh scattering cross-sections, and absorption cross-sections for these gases.

High-Efficiency Relativistic Generators of Nanosecond Pulses in the Millimeter-Wavelength Range

2019 ◽  
Vol 62 (7-8) ◽  
pp. 467-471
Author(s):  
V. V. Rostov ◽  
R. V. Tsygankov ◽  
A. S. Stepchenko ◽  
O. B. Koval’chuk ◽  
K. A. Sharypov ◽  
...  
Keyword(s):  
Wavelength Range ◽  
High Efficiency ◽  
Millimeter Wavelength ◽  
Nanosecond Pulses
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