A SELECTIVELY PUMPED Y3AL5O12 - TM3-CRYSTAL (F-3(4)-]H-4(5)) LASER()

Formation of population inversion and lasing properties of a YAG : Tm3 + laser using the F-3(4) --> H-3(5) transition (lambda = 2.34 mu m) ar e investigated. Laser crystals were pumped by radiation of a ruby lase r, which allowed us to vary the intensity of pumping radiation within a broad range. It is demonstrated that, with the pumping intensity I = 10(24)-10(26) cm(-2) s(-1), the D-1(2) level is efficiently excited t hrough sequential H-3(6) --> F-3(3) --> D-1(2) transitions. Excitation energy at the D-1(2) level is an additional source that pumps the upp er laser level. We suggest that a UV laser could be created using Tm3 ions.