1. Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185, USA
2. Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA

Correspondence to: S. Y. Lin¹ Correspondence and requests for materials should be addressed to S.Y.L. (e-mail: Email: SLIN@sandia.gov).

The ability to confine and control light in three dimensions would have important implications for quantum optics and quantum-optical devices: the modification of black-body radiation, the localization of light to a fraction of a cubic wavelength, and thus the realization of single-mode light-emitting diodes, are but a few examples^{1, 2, 3}. Photonic crystals — the optical analogues of electronic crystal — provide a means for achieving these goals. Combinations of metallic and dielectric materials can be used to obtain the required three-dimensional periodic variations in dielectric constant, but dissipation due to free carrier absorption will limit application of such structures at the technologically useful infrared wavelengths⁴. On the other hand, three-dimensional photonic crystals fabricated in low-loss gallium arsenide show only a weak 'stop band' (that is, range of frequencies at which propagation of light is forbidden) at the wavelengths of interest⁵. Here we report the construction of a three-dimensional infrared photonic crystal on a silicon wafer using relatively standard microelectronics fabrication technology. Our crystal shows a large stop band (10–14.5 m), strong attenuation of light within this band (12 dB per unit cell) and a spectral response uniform to better than 1 per cent over the area of the 6-inch wafer.