Optically Detected Nuclear Magnetic Resonance of Co2+ in LiGa5O8

Optical spectral hole-burning has proven to be a valuable tool for the detection of hyperfine [1] as well as superhyperfine [2] interactions in ground and optically excited states of rare earth ions. In cases where the hole-burning mechanism is population storage in hyperfine or superhyperfine levels of the electronic ground state, the application of an rf-magnetic field resonant with the splittings changes the depth of the spectral hole, which can be monitored either in absorption or in fluorescence [3]. This double resonance technique, commonly termed 'Optically Detected Magnetic Resonance', ODMR (for an overview of applications to rare earth ions see [1]), is in principle able to detect hyperfine as well as superhyperfine [4] splittings of ground and excited [5] states separately. Moreover, the resolution of this technique is determined by the linewidth of the nuclear magnetic resonance and not by the laser linewidth, which only needs to be smaller than the splittings in order to enable spectral hole-burning.