Together with colleagues from France, the physicists of Moscow State University (research group headed by Associate Prof. O.G. Kosareva, Senior Scientific Researcher N.A. Panov, postgrad. stud. V.A. Andreeva, stud. D.E. Shipilo) have deduced the equation for the Hertz vector generalizing the nonparaxial equation of unidirectional propagation of laser radiation for laser effects.
O.G. Kosareva
Relying on the equation deduced, the research group has carried out the digital modelling of laser radiation tight focusing by an ideal thin lens setting a parabolic beam wave front. To verify the results obtained, vector diffraction integrals were used generalizing the Fresnel integral for focusing by a parabolic mirror. The analytical expression for a critical digital aperture has been obtained to define the possibility of describing tight-focusing by a parabolic mirror correctly with the help of the equation for the Hertz vector.
The resulting method of modifying the starting conditions allows one to overcome the problem of incorrect description. The results achieved suggest new opportunities for modelling the nonlinear transformation of a tight-focused femtosecond radiation of powerful terawatt laser systems, including the creation of new sources of terahertz radiation on the basis of microplasma.
The results are published in the article: A. Couairon, O. G. Kosareva, N. A. Panov, D. E. Shipilo, V. A. Andreeva, V. Jukna, and F. Nesa, “Propagation equation for tightfocusing by a parabolic mirror,” Optics Express 23, 31240 (2015).
