Attenuation of optical transmission within the band gap of thin two-dimensional macroporous silicon photonic crystals

The transmissivity within the photonic band gap of two-dimensional photonic crystals of macroporous silicon is reported as a function of crystal thick ness. Measurements were carried out for crystals of nominally 1, 2, 3, and 4 crystal layers using a commercial parametric source, with a wavelength tu nable from 3 to 5 mu m. For wavelengths well within the 3-5 mu m photonic b and gap, attenuation of approximately 10 dB/crystal layer is obtained, in a greement with calculations based on plane wave expansion methods. For these materials, one should be able to achieve photonic crystal functionality in many applications with very small crystal volumes. (C) 1999 American Insti tute of Physics. [S0003-6951(99)01046-3].