Polarization-dependent Rabi frequency beats in the coherent response of Tm3+ in YAG

We experimentally and theoretically investigate the coherent response of Tm3+ ions in yttrium aluminum garnet (YAG). Working on the H-3(6)(1)-->H-3(4)(1) transition we observe optical nutation signals that exhibit multiple distinct Fourier components having polarization-dependent frequencies and weights. This phenomenon is caused by the presence of six different transition-dipole moment orientations of Tm3+ ions in YAG and a resultant dependence of ion-field coupling on field-propagation direction and polarization. Experimental data shown are in excellent agreement with simulation results based on numerical integration of the Maxwell-Bloch equations. [S1050-2937(99)51810-6].