Optical pulse generation with a frequency shifted feedback laser

A pulsed ring dye laser is constructed in which the light is shifted in frequency before being fed back into the gain medium. The active medium is R6G dye pumped by a continuous wave argon-ion laser. An acousto-optic modulator is used to shift the frequency of the light inside the ‘‘cavity.’’ With this device, we have generated optical pulses with a 9.6 ps FWHM of the autocorrelation trace and measured periods as short as 0.9 ns.