A method for estimating the sound absorption coefficient of a material under a synthesized Diffuse Acoustic Field was recently proposed, as an alternative to classical sound absorption measurements in reverberant rooms. Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing the material, estimation of the sound absorption coefficient under a reproduced Diff...

This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. Such measurement settings find applications in medical and geophysical imaging. We show that the absorption coefficient and the spatial component of the scattering coe...

Two sets of hydrogenated microcrystalline silicon thin-film samples were prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at different deposition conditions of excited power and pressure. The correlation between the crystalline volume fraction for the samples determined from Raman spectra and the excited power, pressure, absorption coefficient, refractive index and optica...

We present a semiclassical analysis for the electric dipole absorption of electromagnetic radiation by small metallic particles, in the case where the electron motion is diffusive. We find that there are two contributions to the one-body effective potential: the ‘static’ potential makes a dominant contribution to the absorption coefficient below the frequency ωc = D/a2, and the ‘dynamic’ potent...

In photo-acoustic imaging, energy absorption causes thermo-elastic expansion of optical absorbers, which in turn leads to propagation of a pressure wave. Recently, we have developed an efficient method for locating small absorbing regions inside a bounded domain from boundary measurements of the induced pressure wave and reconstructing the absorbed density. However, it is the absorption coeffic...

This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability resul...

An equation for photons containing a frequency drift term modeling the Doppler effects and an emission absorption coefficient is considered. On the one hand, this frequency drift term involves a coefficient κ relative to the fluid velocity with which the photons interact. This coefficient may vanish, leading to numerical difficulties. On the second hand, the emission absorption σ is known to be...

This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability resul...

Min et al. (2009) presented two complementary techniques that use the diffusion approximation to allow efficient Monte-Carlo radiation transfer in very optically thick regions: a modified random walk and a partial diffusion approximation. In this note, I show that the calculations required for the modified random walk method can be significantly simplified. In particular, the diffusion coeffici...

Amorphous Se40-xTe60Snx glassy alloys have been synthesized by thermal evaporation technique under high vacuum conditions (~ 10 -5 torr). The optical spectra of amorphous Se40-xTe60Snx (x = 0, 2, 4, 6, 8) thin films have been measured by a double beam UV-VIS-NIR computer controlled spectrophotometer over the range of 200-3000 nm. Swanepole technique has been used to calculate the optical consta...