Infrared Refractive Index of Thin YBa2Cu307 Superconducting Films

1992 ◽  
Vol 114 (3) ◽  
pp. 644-652 ◽  
Author(s):  
Z. M. Zhang ◽  
B. I. Choi ◽  
T. A. Le ◽  
M. I. Flik ◽  
M. P. Siegal ◽  
...  
Keyword(s):  
Refractive Index ◽  
Complex Refractive Index ◽  
Wavelength Region ◽  
Wave Theory ◽  
Superconducting Films ◽  
High Tc ◽  
Thin Film Optics ◽  
Infrared Spectrometer ◽  
Thickness Independent ◽  
Constant Refractive Index

This work investigates whether thin-film optics with a constant refractive index can be applied to high-Tc superconducting thin films. The reflectance and transmittance of YBa2Cu3O7 films on LaAlO3 substrates are measured using a Fourier-transform infrared spectrometer at wavelengths from 1 to 100 μm at room temperature. The reflectance of these superconducting films at 10 K in the wavelength region from 2.5 to 25 μm is measured using a cryogenic reflectance accessory. The film thickness varies from 10 to 200 nm. By modeling the frequency-dependent complex conductivity in the normal and superconducting states and applying electromagnetic-wave theory, the complex refractive index of YBa2Cu3O7 films is obtained with a fitting technique. It is found that a thickness-independent refractive index can be applied even to a 25 nm film, and average values of the spectral refractive index for film thicknesses between 25 and 200 nm are recommended for engineering applications.

scholarly journals Empirical formulation of broadband complex refractive index spectra of single-chirality carbon nanotube assembly

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Taishi Nishihara ◽  
Akira Takakura ◽  
Masafumi Shimasaki ◽  
Kazunari Matsuda ◽  
Takeshi Tanaka ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Refractive Index ◽  
Carbon Nanotube ◽  
Complex Refractive Index ◽  
Wavelength Region ◽  
Refractive Indices ◽  
Gel Chromatography ◽  
Optical Resonances ◽  
Visible Wavelength ◽  
Nanotube Membranes

Abstract Assemblies of single-walled carbon nanotubes with a specific chiral structure are promising future optofunctional materials because of their strong light–matter coupling arising from sharp optical resonances of quasi-one-dimensional excitons. Their strong optical resonances, which lie in the infrared-to-visible wavelength region, can be selected by their chiralities, and this selectivity promises a wide range of applications including photonic and thermo-optic devices. However, the broadband complex optical spectra of single-chirality carbon nanotube assemblies are scarce in the literature, which has prevented researchers and engineers from designing devices using them. Here, we experimentally determine broadband complex refractive index spectra of single-chirality carbon nanotube assemblies. Free-standing carbon nanotube membranes and those placed on sapphire substrates were fabricated via filtration of the nanotube solution prepared by the separation method using gel chromatography. Transmission and reflection spectra were measured in the mid-infrared to visible wavelength region, and the complex refractive indices of nanotube assemblies were determined as a function of photon energy. The real and imaginary parts of the refractive indices of the nanotube membrane with a bulk density of 1 g cm−3 at the first subband exciton resonance were determined to be approximately 2.7–3.6 and 1.3i–2.4i, respectively. We propose an empirical formula that phenomenologically describes the complex refractive index spectra of various single-chirality nanotube membranes, which can facilitate the design of photonic devices using carbon nanotubes as the material.

Internal Distribution of Radiant Absorption in a Spherical Particle

1991 ◽  
Vol 113 (2) ◽  
pp. 407-412 ◽  
Author(s):  
A. Tuntomo ◽  
C. L. Tien ◽  
S. H. Park
Keyword(s):  
Refractive Index ◽  
Electromagnetic Wave ◽  
Spherical Particle ◽  
Complex Refractive Index ◽  
General Pattern ◽  
Wave Theory ◽  
Internal Field ◽  
Geometrical Optics ◽  
Small Spherical Particle ◽  
Internal Distribution

This paper applies electromagnetic wave theory for the study of the internal radiant absorption field of a small spherical particle, particularly to determine the optimum combination of size-to-wavelength parameter and complex refractive index for maximum local peak absorption. A map is devised to illustrate the general pattern of the internal field, which can be divided into three main regimes: uniform, front-concentrated, and back-concentrated absorption. In addition, the current study employs geometrical optics to investigate the internal field of radiant absorption. A comparison between the results from the geometrical optics approach to those from electromagnetic wave theory shows that the error involved in the geometrical optics approach increases sharply with the real part of the complex refractive index. A criterion is established to define the region of the applicability of geometrical optics.

Noise of high-Tc superconducting films and bolometers

1998 ◽  
Vol 08 (PR3) ◽  
pp. Pr3-293-Pr3-296
Author(s):  
I. A. Khrebtov ◽  
V. N. Leonov ◽  
A. D. Tkachenko ◽  
P. V. Bratukhin ◽  
A. A. Ivanov ◽  
...  
Keyword(s):  
Superconducting Films ◽  
High Tc

scholarly journals Broadband spectroscopy of astrophysical ice analogues

2019 ◽  
Vol 629 ◽  
pp. A112 ◽  
Author(s):  
B. M. Giuliano ◽  
A. A. Gavdush ◽  
B. Müller ◽  
K. I. Zaytsev ◽  
T. Grassi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Far Infrared ◽  
Infrared Region ◽  
Thz Radiation ◽  
The Real ◽  
Thz Range ◽  
The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

The complex refractive index of dusty plasma

Optik ◽  
2019 ◽  
Vol 194 ◽  
pp. 163078
Author(s):  
Xu Meng ◽  
Chen Yun-yun ◽  
Cui Fen-ping
Keyword(s):  
Refractive Index ◽  
Dusty Plasma ◽  
Complex Refractive Index

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.

The complex refractive index of aerosols during LACE 98 as derived from the analysis of individual particles

2001 ◽  
Vol 32 ◽  
pp. 683-684
Author(s):  
M. EBERT ◽  
S. WEINBRUCH ◽  
A. RAUSCH ◽  
G. GORZAWSKI ◽  
H. WEX ◽  
...  
Keyword(s):  
Refractive Index ◽  
Complex Refractive Index ◽  
Individual Particles

scholarly journals Optimising the Complex Refractive Index Model for Estimating the Permittivity of Heterogeneous Concrete Models

2021 ◽  
Vol 13 (4) ◽  
pp. 723
Author(s):  
Hossain Zadhoush ◽  
Antonios Giannopoulos ◽  
Iraklis Giannakis
Keyword(s):  
Refractive Index ◽  
Shape Factor ◽  
Complex Refractive Index ◽  
Fdtd Method ◽  
Air Voids ◽  
Water Fraction ◽  
Index Model ◽  
General Complex ◽  
Ground Penetrating ◽  
Fine Tune

Estimating the permittivity of heterogeneous mixtures based on the permittivity of their components is of high importance with many applications in ground penetrating radar (GPR) and in electrodynamics-based sensing in general. Complex Refractive Index Model (CRIM) is the most mainstream approach for estimating the bulk permittivity of heterogeneous materials and has been widely applied for GPR applications. The popularity of CRIM is primarily based on its simplicity while its accuracy has never been rigorously tested. In the current study, an optimised shape factor is derived that is fine-tuned for modelling the dielectric properties of concrete. The bulk permittivity of concrete is expressed with respect to its components i.e., aggregate particles, cement particles, air-voids and volumetric water fraction. Different combinations of the above materials are accurately modelled using the Finite-Difference Time-Domain (FDTD) method. The numerically estimated bulk permittivity is then used to fine-tune the shape factor of the CRIM model. Then, using laboratory measurements it is shown that the revised CRIM model over-performs the default shape factor and provides with more accurate estimations of the bulk permittivity of concrete.

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