Doubly resonant coherent anti-Stokes Raman spectroscopy of Ce3+ in LuPO4.

Abstract

We have measured coherent anti-Stokes Raman spectra between crystal-field levels of the $^{2}$${\mathit{F}}_{5/2}$ and $^{2}$${\mathit{F}}_{7/2}$ manifolds of the ${\mathrm{Ce}}^{3+}$ ion diluted in ${\mathrm{LuPO}}_{4}$ at \ensuremath{\sim}10 K. The anti-Stokes signal is nearly resonant with the lowest crystal-field level of the 5${\mathit{d}}^{1}$ configuration of ${\mathrm{Ce}}^{3+}$ at 30 460 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. For a ${\mathrm{LuPO}}_{4}$ crystal doped with 0.06 mol % ${\mathrm{Ce}}^{3+}$, we found enhancements of the third-order susceptibility \ensuremath{\Vert}${\mathrm{\ensuremath{\chi}}}^{(3)\mathrm{R}}$/${\mathrm{\ensuremath{\chi}}}^{(3)\mathrm{NR}}$\ensuremath{\Vert} as high as 11.6. This enhancement is over 20 times larger than that seen previously in singly resonant experiments with pure rare-earth crystals.