Application of shape memory alloy as detector material for far-infrared imaging transducers

Abstract

Based on the thermo-mechanical deformation property of shape memory alloys (SMAs), a nickel-titanium shape memory alloy (NiTi SMA) is used to construct an infrared imaging device. The NiTi SMA device is in the form of a thin film cantilever pixel. The absorption of energy from the impinging infrared radiation changes the horizontal tilt of the pixel due to the reverse martensitic transformation of NiTi SMA. The tilt angle change can be detected by illuminating the cantilever using a laser beam. One can therefore generate an IR image by monitoring the optical reflection from the thin film cantilever pixel. The possibility of realizing a practical low-cost infrared imaging device operating under room temperature conditions is envisaged.