Nonlinear processes of optical excitation and ultrafast optical switching in solid systems of different dimensionalities

The studies are concerned with fundamentally new optical processes in intrinsic and extrinsic crystals and nanostructures of various types. The processes are distinguished by the extremely high degree of nonlinearity and based on the effects associated with transformation of electron band spectra of materials in the field of a high-intensity electromagnetic wave or with photon-avalanche-type phenomena. The key component of the last-mentioned phenomena is defined by electronic transitions such that the corresponding elementary event involves the absorption of one or several photons and the energy transfer between electrons.