3D harnessing of light with 2.5D photonic crystals

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 ID 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. [GRAPHICS] Examples of 2.5D photonic structures. a) A monolithic version, where a vertical stack of III-V semiconductor micro-structured membranes are suspended by surface micromachining. b) A heterogeneous version, where vertical integration of active and passive micro-structured membranes is achieved by bonding technologies. (C) 2010 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim