Integrated spectral and displacement sensors based on nanomechanical photonic crystals

We report a nanophotonic sensor where the key functionalities of actuation, sensing and read-out are integrated in the same device. It is based on electromechanically-tuneable double-membrane photonic crystal cavities, where the resonant wavelength depends on the separation between the membranes. The output is provided directly in the form of a current, removing the need for external optical read-out. It can be used to measure the spectrum of incident light, to determine the wavelength of a laser line with pm-range resolution, or equivalently to measure tiny displacements. Additionally, the integrated actuation makes it suitable for applications where motion control is needed. (9755-51)