Coherent Tunneling by Nonadiabatic Passage in a Three-Waveguide Coupler

We propose a nonadiabatic tunneling technique, which is different from the stimulated Raman adiabatic passage, to improve the optical tunneling efficiency of a three-waveguide system. The theoretical calculations and results show that the tunneling efficiency can reach 100%. The exact analytic solutions to the nonadiabatic tunneling dynamics are presented. Light dynamics in the optical coupler enable a direct visualization of the population transfer of atomic system under generalized pi pulses technique.