Gigahertz optical modulation resulting from coherent lattice oscillations induced by femtosecond laser pumping of 2D photonic crystals of gold-capped polystyrene microspheres

A gigahertz all-optical modulation technique, based on a mechanism in which the modulation of the transmitted light is caused by the coherent oscillation of the phonon modes of gold caps on periodic polystyrene sphere monolayer arrays, is demonstrated. The modulation frequency can be tuned by changing the size of the polystyrene spheres.