We demonstrate an all-optical circular polarization switching (AOCPS) phenomenon by using the storing polarization effect in a photo chemically etched silicon (PCE Si). The luminescence, structural and, chemical characteristics of the PCE Si are also observed, and are compared with the porous silicon (PS). In addition, the mechanism of an AOCPS phenomenon is discussed in terms of interaction between spinning electrons and circularly polarized photons. (C) 2003 Elsevier Science B.V. All rights reserved.