A method is presented for the preparation of double-sided porous silicon (pSi) wafers using a conductive elastomer electrode. The technique enables the fabrication of laterally highly uniform layers of pSi, and the creation of transmissive pSi-based optical components. The use of the conductive elastomer requires no pre- or postprocessing of the silicon starting wafer. The method demonstrates high reproducibility when the two pSi layers are formed under identical experimental conditions, exhibiting differences in pSi film thickness between the front and back side of < 2% over a 254 nm thick pSi film. (c) 2007 The Electrochemical Society.