Photonic crystal thin-film micro-pressure sensors

We have engineered both the optical and mechanical behaviour of a suspended line defect photonic crystal waveguide to demonstrate an improved sensor response. Utilizing thinner than the conventional photonic crystal membrane increases the mechanical sensitivity and the dynamic range of the sensor. The mechanical sensitivity is also increased by optimizing the membrane pad connected to the core photonic crystal waveguide. The pad optimization also ensures maximum pad flatness under uniform pressure. The overall sensitivity obtained is as high as 6 % optical transmission change per Pa of pressure.