MEMS-based meta-emitter with actively tunable radiation power characteristic.

We propose a meta-emitter based on micro-electro-mechanical system (MEMS) technology. The main structure of the meta-emitter unit cell is composed of four symmetrically split crosses of Au and SiO bilayer cantilevers. By changing the size of the cantilevers, this MEMS-based meta-emitter can realize the tunable perfect absorption, and the absorption spectrum is within the longwave infrared (LWIR) wavelength from 8.90 to 11.90 µm. When the surface temperature of the meta-emitter rises, the electrothermal actuation mechanism is performed through the different thermal expansion coefficient (TEC) of the bilayer cantilevers. Therefore, the cantilevers will be bent downward and the bending height of the cantilevers decreases linearly. In such case, the peak value of thermal radiation power can be tuned from the wavelength of 9.52 µm to 10.48 µm when the temperature of meta-emitter is increased from 293 to 1290 K. This proposed MEMS-based meta-emitter is an excellent LWIR light source and has potential application prospects in gas sensing, infrared spectroscopy analysis, medical care and so on.