Near-infrared Yablonovite-like photonic crystals by focused-ion-beam etching of macroporous silicon

Abstract
We report on the fabrication of three-dimensional (3D) Yablonovite-like photonic crystals by focused-ion-beam (FIB) etching of macroporous silicon. Crystals containing up to 25×25×5 lattice cells are fabricated with a submicronic period of ∼0.75 μm. Photonic band gaps at wavelengths close to 3 μm are demonstrated from reflection measurements and confirmed by numerical calculations. The combination of plasma or chemical etching with FIB micromachining appears to be promising for the fabrication of a large variety of multiple-period 3D photonic crystals at optical wavelengths.