Arbitrary-lattice photonic crystals created by multiphoton microfabrication

We used voxels of an intensely modified refractive index generated by multi photon absorption at the focus of femtosecond laser pulses in Ge-doped sili ca as photonic atoms to build photonic lattices. The voxels were spatially organized in the same way as atoms arrayed in actual crystals, and a Bragg- like diffraction from the photonic atoms was evidenced by a photonic bandga p (PBG) effect Postfabrication annealing was found to be essential for redu cing random scattering and therefore enhancing PEG. This technique has an i ntrinsic capability of individually addressing single atoms. Therefore the introduction of defect structures was much facilitated, making the techniqu e quite appealing for photonic research and applications. (C) 2001 Optical Society of America.