DISTRIBUTED-FEEDBACK COLOR-CENTER LASERS USING N-2 CENTERS IN KCL

We report on a distrihuted-feedback (DFB) color center laser based on N-2 centers in KCl. A periodic grating with fringe spacings as fine as 440 nm was produced by means of a two-photon coloration process using two interfering beams. Coloration and photoaggregation processes and the DFB laser action can be availed by the fourth- and second-harmonic and the fundamental lines of a Q-switched Nd:YAG laser, respectively. The linewidth of the DFB output is less than 0.3 nm in the spectrally important 1300 nm region.