Fast all-optical nuclear spin echo technique based on EIT

Abstract: We demonstrate an all-optical Raman spin echo technique, using electromagneticallyinduced transparency (EIT) to create the pulses required for a spin echo sequence:initialization, pi-rotation, and readout. The first pulse of the sequence inducescoherence directly from a mixed state, and the technique is used to measure the nuclearspin coherence of an inhomogeneously broadened ensemble of rare-earth ions(Pr^{3 +}) in acrystal. The rephasing pi-rotation is shown to offer an advantage of combining therephasing action with the operation of a phase gate, particularly useful in e.g. dynamicdecoupling sequences. In contrast to many previous experiments the sequence does notrequire any preparatory hole burning, which greatly shortens the total duration of thesequence. The effect of the different pulses is characterized by quantum state tomographyand compared with simulations. We demonstrate two applications of the technique:compensating the magnetic field across our sample by monitoring T₂ reductionsfrom stray magnetic fields, and measuring coherence times at temperatures up to 11 K,where standard preparation techniques are difficult to implement. We explore the potentialof the technique, in particular for systems with much shorter T₂, and otherpossible applications. Graphical abstract: [Figure not available: see fulltext.]