A theory for the nonlinear (with respect to the electric field) Faraday effect has been developed and applied to a simple model. Within the framework of this model, our analysis shows that the ratio of the nonlinear Uerdet constant to the linear Uerdet constant is proportional to the intensity of the incident light and depends on the frequency of light, the excitation energy of the model molecu...

Progress in micro-fabrication has enabled not only diffractive optical elements (DOE) but also complex freeform surfaces [1]. Transmissive optical elements can be mainly classified into refractive and diffractive. Ray-tracing techniques are sufficient to explain light propagation through and beyond refractive elements. On the other hand, since interferences are the basis of the diffractive doma...

X-ray radiography is the most readily available imaging modality and has a broad range of applications that spans from diagnosis to intra-operative guidance in cardiac, orthopedics, and trauma procedures. Proper interpretation of the hidden and obscured anatomy in X-ray images remains a challenge and often requires high radiation dose and imaging from several perspectives. In this work, we aim ...

Context. Ground based Cherenkov telescope systems measure astrophysical γ-ray emission against a background of cosmic-ray induced air showers. The subtraction of this background is a major challenge for the extraction of spectra and morphology of γ-ray sources. Aims. The unprecedented sensitivity of the new generation of ground based very-high-energy γ-ray experiments such as H.E.S.S. has lead ...

A comprehensive model of the transmission channel between moving vehicles in realistic environments is presented in this paper. The approach consists of tree major parts: the modelling of the road traffic, the modelling of the environment adjacent to the road and the actual modelling of the wave propagation between the vehicles. A ray-tracing approach is used for the wave propagation, which all...

Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks i...

In the interstellar medium (ISM), formation of complex organic molecules (COMs) is largely facilitated by surface reactions. However, in cold dark clouds, thermal desorption COMs inefficient because lack energy to overcome binding energies grain surface. Non-thermal methods are therefore important explanations for gas-phase detection many that primarily formed on grains. Here we present a new n...