Patent ID: 8259376

Claim:
A method of operating a logical gate using at least one delayed optical router comprising a nonlinear optical medium, wherein the nonlinear optical medium comprises two closely spaced ground states such that a transition between the two ground states is dipole forbidden, and an excited state such that two-photon transitions between the two ground states via the excited state are allowed, the method comprising following steps: a) applying, to the nonlinear optical medium, a first laser beam (P) at a first frequency corresponding to a first transition between a first ground state of the two ground states and the excited state; b) applying, to the nonlinear optical medium, a second laser beam (C) at a second frequency corresponding to a second transition from a second ground state of the ground states to the excited state; c) applying, to the nonlinear optical medium, a third laser beam (A) at a third frequency corresponding to the second transition from the second ground state of the ground states to the excited state; d) adjusting an intensity of the second laser beam (C) such that the first laser beam (P) becomes compressed in space and time by electromagnetically induced transparency (EIT) or coherent population oscillations (CPO) due to a modified absorption and dispersion spectra until leaving the nonlinear optical medium thereby to generate a slow light (S); e) adjusting at least one of intensities of the first laser beam (P), the second laser beam (C), and the third laser beam (A), to generate a nondegenerate four-wave mixing signal (D), wherein the slow light (S) disappears in response to the generation of the nondegenerate four-wave mixing signal (D); and f) using at least one of the generated slow light (S) and the nondegenerate four-wave mixing signal (D) as a result of a logical gate.