Measurement of the Stark effect with subhomogeneous linewidth resolution inEu3+:YAlO3with the use of photon-echo modulation

We report a spectroscopic method for precisely measuring the effects of very small energy-shifting perturbations such as the Stark effect, with subhomogeneous-linewidth resolution. This method combines the conventional 2-pulse photon echo or stimulated photon echo with an interferometric technique based on the manipulation of the optical phase of an absorbing species with the perturbing field. This is illustrated by the Stark effect on the ${}_{}{}^7{}_{}{}^{}$ ${\mathit{F}}_0$ ${\to }^5$ ${\mathit{D}}_0$ transition of ${\mathrm{Eu}}^{3+}$:${\mathrm{YAlO}}_3$, where we measure a Stark coefficient of 33.7 kHz/V ${\mathrm{cm}}^{\mathrm{-}1}$ with a resolution of 1.9 kHz.