Parametric generation of even polarization harmonics in a cubic nonlinear layer

The response of a cubic nonlinear medium to the action of a short-duration laser pulse is considered in the case in which the frequency of the optical radiation is close to the frequency of linear oscillators of the medium. It is shown that it is possible to realize parametric generation of even harmonics under the action of a high-intensity femtosecond pulse (with an amplitude exceeding some critical value), which leads to the formation of a supercontinuum at a certain duration and intensity of the incident pulse.