HETERODYNED KERR EFFECT MEASUREMENTS
Orczyk et al.  developed an optical heterodyned measurement technique that allows this separation to be performed. The method employs a local oscillator beam that mixes with the Kerr effect signal. Appropriate optical phase adjustments between this local oscillator and the nonlinear response of the medium may be used to enhance selectively the contribution from either the real or the imaginary part of the third order susceptibility.