Manoj Jain

Propagation of nonlinear optical pulses in inhomogeneous media

We discuss the propagation of nonlinear optical pulses in dispersive media in the presence of inhomogeneities. Two kinds of inhomogeneities are considered, one arising due to radial variation of the refractive index of the medium and the other due to boundary conditions at the medium boundary, i.e., at the radius of an optical fiber. The wave equation is solved in the presence of these effects, taking an average of the radial dependence. It is shown that inhomogeneities have a remarkable influence on the dispersive properties of the medium, and even at normal dispersion, ’’light’’ pulses can be used for soliton transmission. Numerical results are obtained for a Nd : glass laser (λ=1.06 μm) propagating in SiO2 glass.

Modulation of x-ray absorption cross-section by optical radiation☆

Abstract We consider the deep level absorption of X-rays in the presence of optical radiation. The optical field is considered to be small relative to atomic fields but strongly interacting with the outgoing electron. The parameters which justify this approach are derived and the general expression for the x-ray absorption cross-section as a function of the optical field is obtained.

X-ray photoelectric effect in the presence of laser radiation

Abstract We show here that the energy analyzed X-ray photoelectric current in the presence of laser radiation provides direct observation on multiphoton processes.

Four‐photon parametric amplification in semiconductors

A theoretical study of four‐photon parametric amplification in narrow‐band‐gap semiconductors is made. It is shown that phase matching is achievable in a linear geometry if a magnetic field is employed. Furthermore, a substantial cyclotron resonance enhancement occurs in the presence of a magnetic field. We calculate the growth rates and threshold fields associated with the parametric amplification and conclude that an efficient laser may be designed based on this process.