Objective: To develop active devices in which the terahertz (THz) response can be switched by simply changing the temperature of the device.
Approach: Shape memory alloys composed of nickel and titanium were trained to thermally switch between two different physical geometries. A modest 20°C change in temperature causes the alloy to change its crystal structure resulting in physical deformation of the foil.
Results and Significance: We show the first demonstration of shape memory alloys being used for active THz devices. The metal foil was found to reproducibly cycle between the two geometries over 100 times. Other alloys have been shown to switch over 106 times without fatigue. Work is ongoing to show that such switching can be accomplished electrically.