NASA Langley Research Center has developed a novel optical grating device that dynamically modulates light and is capable of controlling the spectral properties and propagation of light without any moving mechanical components.
Spectral properties can be dynamically controlled using MEMS grating devices but the speed is limited by weight, spring constant, and driving force of the components. Further, the moving parts of these devices can deteriorate with stress and friction.
By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmissivity, and the reflectivity of the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by it. Further, the diffraction patterns can be programmed from an external circuit.
Since the device works with an applied electric or magnetic field alone and without mobile mechanical parts, the operation speed can be very fast when compared with existing MEMS devices. And unlike most MEMS devices, NASA's optical grating device can work both in the transmission and reflection modes.