Investigation of green and red up-converted luminescence in Ho/sup 3+/ doped LiYF/sub 4/

Summary form only given. In recent years up-conversion processes have been intensively studied in many rare-earth doped materials in order to develop new optical devices like infrared quantum detectors or compact all-state solid lasers or to find new efficient phosphors. The Ho/sup 3+/ ion is a promising candidate for up-conversion applications, as efficient cross relaxation processes bring about green and red emission from the /sup 5/S/sub 2/ and /sup 5/F/sub 5/ multiplet, respectively, after excitation into the lower-lying levels. In this work up-conversion processes were investigated at room temperature after excitation into the multiplets of Ho/sup 3+/ in LiYF/sub 4/ (YLF).