scholarly journals Determination of the optical properties of three-layered turbid media in the time domain using the P3 approximation

OSA Continuum ◽  
2019 ◽  
Vol 2 (6) ◽  
pp. 1889 ◽  
Author(s):  
Simeon Geiger ◽  
Dominik Reitzle ◽  
André Liemert ◽  
Alwin Kienle
Keyword(s):  
Optical Properties ◽  
Time Domain ◽  
Turbid Media ◽  
The Time Domain

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.

scholarly journals Distribution of Characteristic Times: A High-Resolution Spectrum Approach for Visualizing Chemical Relaxation and Resolving Kinetic Parameters of Ionic-Electronic Conducting Ceramic Oxides

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1240
Author(s):  
Fuyao Yan ◽  
Yiheng Wang ◽  
Ying Yang ◽  
Lei Zhu ◽  
Hui Hu ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Time Domain ◽  
Bulk Diffusion ◽  
High Resolution Spectrum ◽  
Surface Exchange ◽  
Ceramic Oxides ◽  
Fitting Procedure ◽  
The Time Domain ◽  
Rate Limiting

Surface exchange coefficient (k) and bulk diffusion coefficient (D) are important properties to evaluate the performance of mixed ionic-electronic conducting (MIEC) ceramic oxides for use in energy conversion devices, such as solid oxide fuel cells. The values of k and D are usually estimated by a non-linear curve fitting procedure based on electrical conductivity relaxation (ECR) measurement. However, the rate-limiting mechanism (or the availability of k and D) and the experimental imperfections (such as flush delay for gaseous composition change, τf) are not reflected explicitly in the time–domain ECR data, and the accuracy of k and D demands a careful sensitivity analysis of the fitting error. Here, the distribution of characteristic times (DCT) converted from time–domain ECR data is proposed to overcome the above challenges. It is demonstrated that, from the DCT spectrum, the rate-limiting mechanism and the effect of τf are easily recognized, and the values of k, D and τf can be determined conjunctly. A strong robustness of determination of k and D is verified using noise-containing ECR data. The DCT spectrum opens up a way towards visible and credible determination of kinetic parameters of MIEC ceramic oxides.

scholarly journals Laser optoacoustic imaging of turbid media: determination of optical properties by comparison with diffusion theory and Monte Carlo simulation

1996 ◽  
Author(s):  
Alexander A. Oraevsky ◽  
Rinat O. Esenaliev ◽  
Frank K. Tittel ◽  
Martin R. Ostermeyer ◽  
Lihong V. Wang ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Optical Properties ◽  
Diffusion Theory ◽  
Turbid Media ◽  
Optoacoustic Imaging
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