EXTREMELY LOW EXCITATION THRESHOLD, SUPERRADIANT, MOLECULAR AGGREGATELASING SYSTEM

An extremely low threshold for lasing from a specially formulated syst em involving self-assembled, aggregated molecules enables the system t o function as a mirrorless laser. Superradiant energy states created i n coherently coupled aggregated molecules emit photons that stimulate emission from other spatially distributed superradiant states. This st udy focuses on a cyanine dye (specifically, hyl-5,5',6,6'-tetrachlorob enzimidazolocarbocyanine iodide) adsorbed onto silica colloid on which the dye aggregates, forming excitonic states involving coherent domai ns in which a finite number of molecules act cooperatively in the proc ess of emitting photons. It is found that lasing from such a system is induced at a threshold of ca. 39 pJ/pulse, which corresponds to a fac tor of 3x10(+4) times smaller than the lowest lasing threshold reporte d in the literature. (C) 1997 American Institute of Physics.