In the lin⊥lin configuration cooling is achieved via a Sisyphus effect. Consider two counterpropagating electromagnetic waves with equal amplitude and orthogonal linear polarizations E 1 → → = E 0 e i k z x ^ ^ and E 2 → → = E 0 e − − i k z y ^ ^ , where k is the wavenumber k = 2 π π λ λ . The superposition of E 1 → → and E 2 → → is given as: