Persistent spectral hole burning due to deuteron tunneling in SrF₂:Pr³+:D⁻

We report the observation of persistent spectral hole burning due to a mechanism that is new to inorganic materials, i.e., light-induced deuteron (or proton) tunneling. Measurements were made on 3H4 ↔ ID2 transitions of SrF2+ centers having two D− ions as near neighbors. The spectral holes exhibit hyperfine structure dominated by very large (~100-MHz) pseudoquadrupole splittings in the singlet ground state. © 1987 Optical Society of America.