In the framework of a two-moment photo-hydrodynamic modelling of radiation transport, we introduce a concept for the determination of effective radiation transport coefficients based on the minimization of the local entropy production rate of radiation and matter. The method provides the nonequilibrium photon distribution from which the effective absorption coefficients and the variable Eddingt...

We show analytically and numerically that highly dispersive media can be used to drastically increase lifetimes of high- Q microresonators. In such a resonator, lifetime is limited either by undesired coupling to radiation, or by intrinsic absorption of the constituent materials. The presence of dispersion weakens coupling to the undesired radiation modes and also effectively reduces the materi...

The NDIR gas detection method is based on the absorption of infrared radiation, which is shown by many polyatomic or heterodimer diatomic gases. For example CO2 gas absorbs IR radiation at 4.26μm wavelength. The detected radiation intensity at this wavelength decreases if the concentration of CO2 increases between source and detector. The extent of absorption mainly depends on the absolute numb...

We examine the interactions of radiation with a hydrogen-like atom as a simple example that displays many of the typical characteristics of how atoms and molecules in general interact with photons. We will examine the spectral line processes of absorption, stimulated emission (emission caused by passing radiation), spontaneous emission (radiation without any external stimulus), and the continuu...

Titanium alloys have found numerous applications in space research, and nuclear industry and research. Since X-rays constitute an important part of the space radiation environment, numerical simulations of radiation absorption characteristics of titanium alloys were studied in this paper. The photon transport Monte Carlo software was used for determining the energy deposited in titanium samples...

In this research, Ag nanoparticles were prepared by using g-radiation at concentration of 5.18×10-3 M and irradiated at different doses. A green laser was employed as excited source for measuring nonlinear refractive index and absorption coefficient. The measurements were done by z-scan method for both, closed and open aperture at temperature room. We deduced that with growth of size of Ag nano...

It is well known that most crystals which show Reststrahlen behavior are nearly transparent at low temperatures for far-infrared radiation at frequencies below the infrared active eigen-frequency. The crystals are nearly opaque at room temperature due to strong absorption by phonon combination processes [1]. We report experimental results which show that for T1C1 a pronounced LA-TA two phonon d...

The effects of electromagnetic fields (EMFs) radiation at the frequency of 940 MHz on the structure and function of human adult and fetal hemoglobin (HbA and HbF) were studied. After extraction and purification of HbA and HbF, the oxygen absorption values for exposed and unexposed HbA and HbF to EMF were compared. The slope of oxygen absorption curve for exposed HbA was increased while that for...