|
Coherent manipulation of spins at low temperature is an important ingredient in applications such as spintronics and quantum computing. Electron-spin resonance is a versatile probe of the electronic environment in radicals. Even ESR silent species can be explored by appending radical spin tags. Because direct detection of electron spin resonance (ESR) on doped helium nanodroplets lacks the necessary sensitivity, we exploit optically-detected magnetic resonance (ODMR). We measure sharp, hyperfine-resolved, ESR spectra of single K and Rb atoms isolated on He nanodroplets. The shift of the ESR lines with respect to free atoms directly reflects the distortion of the valence-electron wavefunction due to the He nanodroplet and denotes in an increase of the hyperfine constant consistent with an increase of the Fermi contact interaction. We are able to follow this change as a function of droplet size attesting the sensitivity of the method for many foreseeable applications. The observation of Rabi oscillations indicates a long decoherence time and proves our ability to perform coherent manipulation of the spin. |
|