Geometrical representation of coherent tunneling process in two-waveguide and three-waveguide coupler Project supported by the National Natural Science Foundation of China (Grant Nos. 11304247 and 61505161) and the Shaanxi Provincial Research Plan for Young Scientific and Technological New Stars, China (Grant No. 2015KJXX-40). |
(color online) Geometrical representation of ideal STIRAP in three-waveguide directional coupler, the central waveguide is not excited. |