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Fluorescence and Upconversion in CaF 2 :Ho 3+
Author(s) -
Tang S. H.,
Zhang H. Y.,
Kuok M. H.,
Kee S. C.
Publication year - 1991
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221680134
Subject(s) - fluorescence , photon upconversion , relaxation (psychology) , ion , absorption (acoustics) , atomic physics , analytical chemistry (journal) , excitation , laser , chemistry , wavelength , laser induced fluorescence , materials science , optics , physics , optoelectronics , chromatography , social psychology , psychology , organic chemistry , quantum mechanics , composite material
Laser excitation studies of CaF 2 crystals doped with 0.01 to 10% Ho 3+ using the second harmonic wavelength 532 nm of a pulsed Nd: YAG laser are carried out. Three fluorescence bands belonging to the 5 F 4 , 5 S 2 → 5 I 8 , 5 F 4 , 5 S 2 → 5 I 7 and 5 F 5 → 5 I 8 transitions are detected. Fluorescence lifetimes of the first two transitions are measured and used for site‐identification of new lines. Four upconverted fluorescence bands belonging to the 5 F 3 → 5 I 8 , 5 G 4 → 5 I 8 , 5 G 5 → 5 I 8 , 5 H 5 , 5 H 6 → 5 I 8 transitions are also detected. A comparative study is made of two pairs of energy transfer mechanisms, which are multiphonon relaxation versus ion‐pair relaxation and two‐photon absorption versus ion‐pair relaxation. The analysis of the concentration dependence of fluorescence intensities shows that ion‐pair relaxation is the chief mechanism responsible for the fluorescence and upconversion behaviour of CaF 2 :Ho 3+ .