Single-atom transistor for light

摘要

In a nonlinear optical medium, the electric polarization induced by an incident light beam (or beams) exhibits a nonlinear dependence on the light's electric field. This nonlinearity, which can give rise to optical effects such as harmonic generation, or an intensity-dependent refractive index (the optical Kerr effect), is typically very small and limited in usefulness by absorption of the beam when the frequency of light is too close to an atomic resonance in the medium. Consequently, nonlinear optical effects are generally associated with bulk media and high-intensity light fields far from resonance with atomic transitions.