Delayed optical router/switch

A method of delayed optical switch using a nonlinear optical medium composing 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 m transitions between the two ground states via the excited state are allowed, the method comprising following steps:

• a) producing a slow light, by using a first laser beam with a first frequency corresponding to a first transition between a first ground state of the two ground states and the excited state and a second laser beam with a second frequency corresponding to a second transition between a second ground state of the two ground states and the excited state;
• b) producing a nondegenerate four-wave mixing signal, by using the first laser beam with the first frequency, the second laser beam with the second frequency and a third laser beam C2 with a third frequency corresponding to the second transition between the second ground state of the two ground states and the excited state;
• wherein the slow light is disappeared in response to the producing of the nondegenerate four-wave mixing generation or a phase conjugate;
• and
• c) connecting the nondegenerate four-wave mixing signal or the slow light to free space or to optical fibers.

An apparatus for delayed optical router, said apparatus comprising:

• a nonlinear optical medium composing two closely spaced ground states such that a transition between said two ground states is dipole forbidden, and an excited state such that two-photon transitions between said two ground states via said excited state are allowed;
• a first laser beam source for generating a first laser beam (P) at a first frequency corresponding to a first transition between a first ground state of said two ground state and said excited state and for applying, to said nonlinear optical medium, said first laser beam (P);
• a second laser beam source for generating a second laser beam (C1) at a second frequency corresponding to a second transition between a second ground state of said two ground state and said excited state, and for applying, to said nonlinear optical medium, said second laser beam (C1);
• a first means for applying, to said nonlinear optical medium, a third laser beam (C2) at a third frequency corresponding to said second transition between said second ground state and said excited state;
• a second means for adjusting at least one of an intensity and a frequency of at least one of said second laser beam (C1) and said third laser beam (C2), so that a slow light (S) is produced using said first laser beam (P) and a nondegenerate four-wave mixing signal (D) is produced using said third laser beam (C2);
• and
• a third means for connecting said slow light (S) or said signal (D) to said nonlinear optical medium.

An apparatus for delayed optical router, said apparatus comprising:

• a nonlinear optical medium composing two closely spaced ground states such that a transition between said two ground states is dipole forbidden, and an excited state such that two-photon transitions between said two ground states via said excited state are allowed;
• a first means for applying a first laser beam, a second laser beam and a third laser beam to said nonlinear optical medium, wherein the first laser beam has a first frequency corresponding to a first transition between a first ground state of said two ground state and said excited state, the second laser beam has a second frequency corresponding to a second transition between a second ground state of said two ground state and said excited state, and the third laser beam has a third frequency corresponding to the second transition;
• and
• a second means for adjusting at least one of an intensity and a frequency of at least one of said second laser beam and said third laser beam, so that a slow light is produced using said first laser beam and a nondegenerate four-wave mixing signal is produced using said third laser beam.