New dye laser systems with dynamic distributed feedback

Optical dye laser systems with dynamic distributed feedback are proposed; these systems make it possible to tune the stimulated emission frequency over the whole gain profile of typical dyes without a superfluorescence background. The dominant-mode stimulated emission threshold of these lasers is lowered relative to the superfluorescence threshold as a result of the formation of a dynamic amplitude–phase grating in the active medium having an efficiency independent of the degree of mutual coherence of the pump source. Estimates are made of parameters of a thermal phase grating.such as the lifetime and reflection coefficient in typical solvents.