Rydberg-state species in a strong laser field

A brief state-of-art review of the research into the interaction of laser radiation with Rydberg atoms and clusters of Rydberg atoms is provided. The dynamics of various Rydberg species in a high-frequency optical field is described with the use of the quantum-mechanical approach. Experimental data indicating the existence of Rydberg-state species (Rydberg clusters and Rydberg matter) are analyzed. A special emphasis is placed on Raman processes in Rydberg atoms and Rydberg matter created on solid surfaces.