2-DIMENSIONAL INFRARED PHOTONIC CRYSTAL BASED ON MACROPOROUS SILICON

The propagation of electromagnetic radiation in periodic dielectric me dia can be described similar to the case of electrons propagating in a crystal. A photonic bandgap, a frequency range where no electromagnet ic modes exist, may open up in two or three dimensions and greatly aff ect the radiative dynamics within the structure. Requiring wavelength- scale structures, a photonic band material for optical and infrared fr equencies is at the limit of today's fabrication techniques. Macroporo us silicon offers a way to meet the requirements of regularity and hig h refractive index contrast for a two-dimensional (2D) photonic materi al in the infrared regime. By controlled formation of macropores in n- type silicon, we fabricated a 2D photonic lattice with photonic bandga ps in the infrared region between 250 and 500 cm(-1) (20-40 mu m). The transmission spectra between 50 and 650 cm(-1) were in good agreement with the theoretically calculated structure.