Observation of sub-Doppler Laser Induced Nuclear Orientation of 85mRb

This paper reports on the first observation of sub-Doppler resolved gamma anisotropy produced by Laser Induced Nuclear Orientation (LINO). The anisotropy was produced by laser optical pumping the Dl transition of the 1μs 85mRb isomer. Sub-Doppler LINO is uniquely suited for resolving closely spaced hyperfine structure (hfs) of very shortlived isomers, whose lifetimes are between 50 nanoseconds and 1 milli-second. In addition, sub-Doppler LINO allows more precise measurements of hf splittings to be made. For example, this leads to more accurate measurements of nuclear magnetic dipole and electric quadrupole moments, as well as isomer shifts. LINO uses laser optical pumping to produce electronic alignment. This is transferred to the excited nucleus via the hyperfine interaction. When the oriented nuclei decay, anisotropy is observed in the spatial distribution of the emitted gamma rays. The hfs of the isomer is determined by monitoring the anisotropy as a function of laser detuning