Transmittance tuning of photonic crystal reflectors using an AFM cantilever

A method is described for mechanically tuning the transmittance of two-dimensional photonic crystal slab reflectors. These reflectors have a triangular lattice of air holes in a silicon waveguide, and the crystals act as optical reflectors because of their photonic band gaps. The transmittance is tuned by inserting the tip of an atomic force microscopy cantilever into one of the air holes; the filled air hole transmits the incident light. Experiment demonstrated that this increases the transmittance 1.1 times, which agrees with calculations using finite difference time domain method. This method can thus be used to mechanically tune the PhC transmittance.