Accumulated photon echo in neodymium-doped disordered yttrium fluoride crystals.

Abstract

Accumulated photon echoes were used to measure the dephasing time (${\mathit{T}}_{2}$) of the $^{4}$${\mathit{I}}_{9/2}$${\ensuremath{\rightarrow}}^{4}$${\mathit{G}}_{5/2}$${,}^{2}$${\mathit{G}}_{7/2}$ transition of ${\mathrm{Nd}}^{3+}$ in highly disordered ${\mathrm{CaF}}_{2}$-${\mathrm{YF}}_{3}$ crystals. ${\mathit{T}}_{2}$ decreased from subnanosecond values for excitation of low-lying Stark levels to subpicosecond values for excitation of high-lying levels. From 9--100 K the measured temperature dependence of the homogeneous linewidth is described by a resonant single-phonon absorption process.