Far-infrared absorption by glass-like features in fluorite mixed crystals

Abstract

The mm- and submillimeter wave spectrum of a glass at low temperatures is often dominated by the dynamics of two level systems (TLS). These E and M properties are reviewed here. Next the low-temperature far-IR absorption measurements on a number of alkaline earth: rare earth fluoride mixed crystals with the fluorite structure are described, compared to the glass results, and found to display a similar frequency distribution of TLS. At higher far IR frequencies a characteristic temperature dependence associated with excited state transitions of the TLS is observed for both mixed crystals and glasses, suggesting a fundamental connection between the TLS in these very different systems.

Publisher

Society of Photo-optical Instrumentation Engineers (SPIE)

Publication Date

12-18-1996

Publication Title

SPIE Proceedings

Department

Physics and Astronomy

Document Type

Article

DOI

https://dx.doi.org/10.1117/12.262754

Language

English

Format

text

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