  We demonstrate a novel technique for cooling a degenerate Fermi gas in a
crossed-beam optical dipole trap, where high-energy atoms can be selectively
removed from the trap by modulating the stiffness of the trapping potential
with anharmonic trapping frequencies. We measure the dependence of the cooling
effect on the frequency and amplitude of the parametric modulations. It is
found that the large anharmonicity along the axial trapping potential allows to
generate a degenerate Fermi gas with anisotropic energy distribution, in which
the cloud energy in the axial direction can be reduced to the ground state
value.
