New infrared fluorescence bands of concentrated solutions of polymethine dye solutions and prospects for development of efficient polymethine lasers

A report is given of the discovery of new infrared fluorescence bands observed on excitation of concentrated solutions of the two polymethine dyes which were the first to be synthesized. The conditions (concentration and nature of excitation) for the appearance of these infrared fluorescence bands were determined and the possible mechanisms of their formation were considered. A discussion is given of the prospects for constructing efficient polymethine lasers emitting in the infrared.