Enhancement of nonlinear response using vibrational resonance in a nonlinear oscillator; sum and difference frequency generation

Abstract

We consider the second order response for nonlinear processes at the sum and difference frequencies of a nonlinear centrosymmetric system to a weak low frequency field excitation in presence of a strong rapidly varying time-periodic field. It is shown that the rapidly varying field breaks the centre of symmetry of the potential and shifts the steady state in such a way that the system becomes susceptible to weak field excitation at an optimal strength of the high frequency field. The magnitude nonlinear response to the weak field is of the order of the linear response in sharp contrast to the usual three-wave mixing processes traditionally carried out in strong laser fields.