Photonic lattices achieved with high-power femtosecond laser microexplosion in transparent solid materials

We propose and utilize ultrashort laser pulses to tailor three-dimensional microstructures and their optical properties. When an intense femtosecond pulse was tightly focused into some transparent materials, a laser-induced microexplosion occurred, generating void holes inside the medium. When the thus-fabricated holes or cylinders were regularly organized, a microstructure with a periodic refractive index distribution was accomplished, which was liable to act as a photonic crystal structure. One-, two, and three-dimensional photonic lattices have been acquired by using this technique. Significant photonic band gap effects were confirmed by transmission measurements. The unique feature of the ultrashort laser micromachining of photonic crystal structures was the availability of arbitrary spatial geometry.