Simplified theory of the impulse response of an optical degenerate four-wave mixing cell

It is shown that the linearized theory of transient degenerate four-wave mixing (DFWM) is analogous to the case of a linear string with nonrigid support, imbedded in a repulsive quadratic potential. The dispersion relation for the latter permits an extremely simple derivation of the impulse response of a finite-length DFWM cell.