MEMS-enabled mechanically-tunable 2D photonic crystal lens

We report design, fabrication and characterization of microelectromechanical systems (MEMS) enabled mechanically tunable 2D photonic crystal lens. The photonic crystal lens was realized by embedding honeycomb lattice silicon nano rods array inside flexible 10 µm thick SU-8 membrane. A pair of chevron shape nickel actuators was used to symmetrically stretch the 2D photonic crystal lens. The induced uniaxial elongation in photonic crystal lens thus perturbs the photonic band structure, leading to modulation of the focal length. The tunable lens was characterized using infrared tunable laser and far field imaging infrared camera. The profiles of the scattered light spot at the deflection at various strains were digitized and carefully compared with 2D finite difference time domain (FDTD) simulations. Both simulation and experiment results were in good agreement.