Layer-by-layer photonic crystals from microwave to far-infrared frequencies

The use of layer-by-layer geometry to build photonic band-gap crystals at various frequencies ranging from microwave to the far-infrared is described. The layer-by-layer structure yields a full photonic band gap in all directions, and this is experimentally confirmed at microwave frequencies. The structures are then built at smaller scales by means of silicon micromachining with photonic band-gap frequencies as high as 500 GHz. Transmission characteristics and the reflection characteristics of the millimeter-wave photonic crystals are reported. The use of laser-micromachined alumina substrates to build three-dimensional millimeter-wave photonic crystals is also described. Defect structures are investigated at microwave and millimeter-wave frequencies. (C) 1996 Optical Society of America.