Optical transparency of macroporous silicon with through pores

Optical transmission spectra of macroporous silicon with through pores has been studied experimentally and theoretically in the spectral range 0.3–0.8 µm (in which single-crystal Si is opaque). The spectra are discussed in terms of the general diffraction theory. Expressions taking into account the diffraction at the entrance and exit of pores and the influence exerted by deviation of the angle of light incidence from the normal are derived. The transmission spectrum is fairly well described by the results of calculation.