Photonic crystal tuned by cantilever

The purpose of our research is to tune two-dimensional (2D) slab photonic crystal (PhC) reflectors by inserting an AFM cantilever into one of the air holes. The 2D slab PhCs have column-shaped air holes on the triangular lattice in silicon air-bridge waveguide. The PhCs act as optical reflectors because of their photonic band gap. First, we estimated the effect of the cantilever insertion on the transmittance of the PhC reflectors with the finite difference time domain (FDTD) method. Then, we fabricated PhC reflectors by electron beam (EB) lithography and DRIE. Finally, we inserted the cantilever into one of their air holes. The transmittance with the cantilever was about twice as large as the original transmittance. The results proved that we could tune the transmittance of the PhC reflectors.