The possibility of gain among the 5d-4f transitions of the rare earth ions

Thesis/Dissertation · Thu Dec 31 04:00:00 EST 1992

OSTI ID:114800

Lawson, J K

Although a wealth of information exists on the 4f-4f transitions of rare earth ions doped into solid-state materials, relatively little research exists on the 5d-4f transitions present in the same materials. We have studied the 5d-4f transitions of three rare-earth ions in a variety of materials in an attempt to evaluate the potential of the 5d-4f transition as a laser transitions. We have measured the pump-probe spectrum of Sm{sup 2+}:CaF{sub 2} over a wide spectral region in order to characterize a material know to lase on a 5d-4f transition. We then measured comparable pump-probe spectra for Sm{sup 2+} in SrF{sub 2} and SrCl{sub 2}. This provided us with a systematic look at the excited state and its dependence on the host material. In addition to investigating divalent samarium, we have investigated other rare-earth ion doped systems similar in nature to known laser systems. Divalent europium, being a neighbor of samarium on the periodic table, has a very similar electronic configuration. Historically, europium has been recognized as an efficient fluorescent material, but has not demonstrated gain in any solid state host. We measured the pump-probe spectrum of divalent europium over a wide spectral region in CaF{sub 2}, SrF{sub 2}, SrCl{sub 2}, and LiCaAlF{sub 6} in order to better understand the nature of the excited states and to evaluate whether it is possible for Eu{sup 2+} to exhibit gain in any host medium. Among the trivalent rare earths, two elements, cerium and neodymium, have been demonstrated to lase. We chose expand upon current knowledge of 5d-4f transitions in the trivalent RE ions by studying trivalent praseodymium in CaF{sub 2}, SrF{sub 2}, BaF{sub 2}, BaY{sub 2}F{sub 8}, and LiYF{sub 4}. Pr{sup 3+} seemed to be a reasonable candidate for gain, in part because it lies on the periodic table between the two elements which exhibit gain as trivalent ions in solid state media.

• Research Organization: California Univ., Davis, CA (United States)
• OSTI ID: 114800
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
ENERGY-LEVEL TRANSITIONS
GAIN
LASER RADIATION
RARE EARTHS