CONTINUOUS SAPPHIRE-TITANIUM LASER WITH R EINJECTION - SIMULTANEOUS EMISSION ON 2 TUNABLE WAVELENGTHS

We have demonstrated that self-injection in a CW Ti3+:Al2O3 produce hi gh efficiency (eta congruent to 15%), narrow-line, two-wavelength emis sion. Self-injection use an original high resolution two-wavelength se lector, combining an interference wedge and a grazing incidence gratin g, and operating outside the non-selective laser cavity, thus avoiding insertion losses and optical damage problems. Wavelength control (fwh m : 0.008 nm) over a 50 nm range has been demonstrated both for linear and for ring laser cavities; in the latter case, self-injection permi ts also to obtain unidirectional behaviour. A 1.5 W, background free, total output power has been obtained simultaneously at two laser lines , in a single beam or in two separated beams. Performances of our orig inal laser device have been checked with single step and two-step exci tation of atomic rubidium vapour.