Control of light propagation and localization in a photonic crystal slab by using a micromechanical actuator

The tuning of the light propagation and localization properties in photonic crystal (PhC) slabs by using microactuators was demonstrated numerically and experimentally. A micromechanical actuator controls the position of the exterior structural element, which is located close to the PhC slab, and modulates the PhC properties through the change of the evanescent interaction of light confined in the PhC slab with the exterior element. When the exterior structural element approaches to a line-defect PhC waveguide, intensity and phase modulations occur. In the preliminary experiment using a line-defect PhC waveguide, we demonstrated the optical switching operation with an extinction ratio of ∼10 dB at a wavelength of 1.55 μm. The localized state of light in a point-defect cavity can also be controlled. The tuning of the resonant wavelength over the spectral range of ∼60nm at around the wavelength of 1.55 μm was numerically demonstrated by combining two PhC slabs. The approach discussed here can be widely employed for realizing functional and tunable PhC slab devices.