Upconversion laser emission has been achieved in BaY2F8:Er 5% by pumping of either the ground state or an excited state of the Er3+ ion. The initial excitation step has been identified with precise measurement data of the Stark level structure of the Er3+ ion in this system. Small increments in the pump wavelength can cause the laser to switch from laser operation in the blue to laser operation in the green because of changes in the specific pumping pathway.
© 1994 Optical Society of America
R. A. McFarlane, "Upconversion laser in BaY2F8:Er 5% pumped by ground-state and excited-state absorption," J. Opt. Soc. Am. B 11, 871-880 (1994)