Structuring of macroporous silicon for applications as photonic crystals

Uniformity and high refractive index contrast make macroporous silicon an i deal two-dimensional photonic crystal, that can be tailored over a wide ran ge of frequencies. For optical transmission measurements the porous silicon has to be structured further. Light has to be coupled in perpendicular to the pore axis and to traverse a well defined number of pore layers. For thi s purpose a lateral structuring technique has been developed that allows to remove the porous silicon with a precision of less than one pore lattice c onstant. Bars of macroporous silicon which are 100 mu m high, 2-200 mu m wi de and several mm long have been prepared. These bars have been aligned wit h designed defect structures like linear or bent waveguides in the porous s ilicon. The achieved samples are well suited to investigate the optical pro perties of these defects with light traveling perpendicular to the pore axi s.