Electrical modulation of emissivity

We demonstrate that it is possible to modulate the thermal emission through an electrical modulation of the emissivity. The basic idea is to design a device where absorption is due to a resonant phenomenon. If the resonance can be electrically controlled, then absorption and, therefore, thermal emission can be controlled. We demonstrate this general concept using THz resonant absorption by surface phonon polaritons coupled through a gold grating. In our device, absorption is mostly due to a surface phonon mode confined in a single quantum well (QW). The THz emissivity is electrically controlled by controlling the quantum well refractive index using a gate voltage to modulate the electron density. This paves the way to electrically modulated incandescent sources. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793650]