Nonlinear optical response of an excited 1/3 laughlin liquid

An ensemble of neutral excitations in a 1/3 Laughlin liquid is studied experimentally. It has been found that excitations induce a nonlinear optical response in the form of a quadratic dependence of the reflection signal on the pump power. The reported experimental results have shown that the observed effect is due to the contribution of the coherent anti-Stokes–Stokes scattering from the excited Laughlin liquid.