Ultraviolet-to-visible luminescent conversion in CaF/sub 2/:Eu/sup 2+/ and SrF/sub 2/:Eu/sup 2+/ crystals

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Journal of the Electrochemical Society; (USA)

DOI:https://doi.org/10.1149/1.2097035· OSTI ID:5200592

Scheps, R ^[1]

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1. Naval Ocean Systems Center, San Diego, CA (USA)

With a fluorescence quantum efficiency of 0.62 and a quantum defect of 0.82, CaF/sub 2/:Eu/sup 2+/ has potentially wide applications in areas where efficient solid-state ultraviolet-to-visible optical converters are desired. The broad 4f {yields} 5d (e/sub g/) absorption is centered at 355 nm, while the 298 {Kappa} emission is centered at 434 nm, so that the ratio of the two photon energies (the quantum defect) times the quantum efficiency gives an overall power conversion efficiency factor of 0.51. Substantial excited state absorption (ESA) at wavelengths within the CaF/sub 2/:Eu/sup 2+/ fluorescence band has been measured and apparently defeats attempts to obtain stimulated emission in this crystal. However, when used as a shield or jacket in a flashlamp-pumped solid-state laser, this luminescent converter can improve the efficiency and lifetime for laser materials that are mostly transparent in the UV and/or develop color centers after repeated UV exposure. For example, flashlamp-pumped Ti:Al/sub 2/O/sub 3/ suffers from both. To better characterize Eu/sup 2+/ - doped hosts for such applications, new measurements of the excitation and emission spectra of CaF/sub 2/:Eu/sup 2+/ and SrF/sub 2/:Eu/sup 2+/ were taken. In addition, radiative lifetimes were calculated and the dependence of the fluorescence intensity and lifetime on crystal temperature and pump fluence were measured and are presented.

• OSTI ID: 5200592
• Journal Information: Journal of the Electrochemical Society; (USA), Journal Name: Journal of the Electrochemical Society; (USA) Vol. 136:6; ISSN 0013-4651; ISSN JESOA
• Country of Publication: United States
• Language: English

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71 CLASSICAL AND QUANTUM MECHANICS
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ALKALINE EARTH METAL COMPOUNDS
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