P.P. Feofilov is one of the most famous soviet scientists. He began his research under the supervision of the Academician S.I. Vavilov.
Feofilov has made a great contribution to the development of physics of crystals doped with transition metal ions. He is one of the first in the world to have begun the systematic investigation of the optical properties of crystals comprising ions with uncompleted shell, e.g. rare earth (RE) ions and uranium. He was the first to state such essential problems as multiple activator sites problem, crystal-chemical conditions of activation, physical structure and energy of the RE-sites.
Feofilov has developed and successfully implemented the method of polarized luminescence for investigation of the RE-sites. The book “Polarized luminescence of molecules, solutions and crystals” now is a classical course book for studying spectroscopy. Feovilov’s investigation of the spectroscopic and luminescent properties of crystals made possible the creation one of the first solid state lasers based on calcium fluoride crystals doped with samarium and uranium.
Feofilov’s researche has a great impact on such areas of solid state physics as crystal chemistry, crystal physics and physics of radiation defects in crystals.
Besides, Feofilov was a friendly, open-minded and talented person.