Abstract
Recent developments in x-ray laser research resulted in the experimental observation of laser amplification at many wavelengths in soft x-ray domain [1] ranging from λ = 280 Å to λ = 42 Å. There is no doubts that within next few years powerful sources of coherent x-ray laser radiation at those wavelengths will also be available. This sets a stage for the research on the interaction of intense coherent x-ray radiation with a matter, in particular on x-ray nonlinear optics. The first obvious choice of the environment and frequency for the nonlinear effects to occur and to be experimentally observed, is the same plasma of ionized atoms that gives rise to the laser action itself, with the nonlinear interaction occurring at the frequency of lasing transition. The nonlinear effects in such a situation are essentially expected to be the same as in any other resonantly-enhanced nonlinear interaction of light with matter in a visible optical domain and could approximately be evaluated using basically two (or three) level model. In order to demonstrate the feasibility of this kind of nonlinear effects both in active and passive x-ray laser medium, we present here evaluations of the characteristic parameters pertinent to the resonant nonlinearity: the saturation driving intensity and nonlinear change of refractive index. We use simple and yet realistic model based on the neonlike Mo XXXIII plasma; observation of soft X-ray amplification in such a system has recently been reported [2]. We show that the third order nonlinear effects, such as saturation of absorption (or gain) and nonlinear refractive index can be observed in the Mo XXXIII amplifier (laser) radiation propagating in such a plasma in the cases of both "hot" laser plasma in the core of the laser system, and "warm" plasma surrounding the core and having considerably lower electron density Ne and temperature Te. Following [3], consider the "warm" plasma with the density Ne sufficiently low such that collisional rates of the quantum levels of interest can be neglected compared with radiative ones.
© 1991 Optical Society of America
PDF ArticleMore Like This
P. L. Shkolnikov and A. E. Kaplan
WA7 Soft X-Ray Projection Lithography (SXRAY) 1991
P. L. Shkolnikov and A. E. Kaplan
MP4 OSA Annual Meeting (FIO) 1991
P. L. Shkolnikov and A. E. Kaplan
WL9 OSA Annual Meeting (FIO) 1991