| Abstract: | It is emphasized that two‐dimensional photonic crystals (2D PC) have not only a great potential for the development of 2D nanophotonics in the inplane waveguided configuration, but that they may also open the way to other brilliant developments, with an extension to out‐of‐plane operation, along a 2.5D nanophotonics approach. In this 2.5D approach, a 1D–2D high index contrast lateral structuration is combined with a 1D high index contrast vertical structuration, using multilayer membrane stacks including 1D–2D photonic crystal membranes, thus resulting in so‐called 2.5D PC. As a specific illustration of recent achievements along this approach, new families of VCSEL structures are presented. |
