John G. Long, Peter C. Searson, et al.
JES
A number of nonlinear upconversion excitation mechanisms have been used to achieve lasing at wavelengths that are shorter than those of the pump light. We found that sequential two-step absorption was the principal process in YAlO3+ and LaF3+ whereas energy transfer upconversion dominated in YLiF4+. A nonlinear absorption process associated with cross relaxation resulted in upconversion lasing in YLiF4+. © 1990.
John G. Long, Peter C. Searson, et al.
JES
E. Burstein
Ferroelectrics
P. Martensson, R.M. Feenstra
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Mark W. Dowley
Solid State Communications