Electronic Zeeman and Stark spectroscopy of BaClF:Sm2+using photon-gated hole burning

The recently demonstrated process of photon-gated spectral hole burning has been used to measure the small frequency shifts necessary for the determination of linear Stark and nonlinear Zeeman coefficients of the 4$f^6$ ${}^7$ $F_0$ $A_1$→${}^5$ $D_0$ $A_1$, ${}_{}{}^5{}_{}{}^{}\mathrm{D}_1^{}{}_{}{}^{}$ ${\mathrm{A}}_2$, and ${}_{}{}^5{}_{}{}^{}\mathrm{D}_1^{}{}_{}{}^{}$E transitions of ${\mathrm{Sm}}^{2+}$ in BaClF. The nonlinear Zeeman coefficients obtained in this way agree, to better than 12%, with those calculated assuming free-ion 4$f^6$ wave functions for ${\mathrm{Sm}}^{2+}$. The Stark splitting coefficients (0.068–0.074 MHz/V ${\mathrm{cm}}^{\mathrm{-}1}$) are smaller than the few previously reported for $f^n$→$f^n$ transitions of rare-earth ions.