Integrated nano-opto-electro-mechanical sensor for spectrometry and nanometrology

Spectrometry is widely used for the characterization of materials, tissues, and gases, and the
need for size and cost scaling is driving the development of mini and microspectrometers.
While nanophotonic devices provide narrowband filtering that can be used for spectrometry,
their practical application has been hampered by the difficulty of integrating tuning and
read-out structures. Here, a nano-opto-electro-mechanical system is presented where the
three functionalities of transduction, actuation, and detection are integrated, resulting in a
high-resolution spectrometer with a micrometer-scale footprint. The system consists of an
electromechanically tunable double-membrane photonic crystal cavity with an integrated
quantum dot photodiode. Using this structure, we demonstrate a resonance modulation
spectroscopy technique that provides subpicometer wavelength resolution. We show its
application in the measurement of narrow gas absorption lines and in the interrogation of
fiber Bragg gratings. We also explore its operation as displacement-to-photocurrent transducer,
demonstrating optomechanical displacement sensing with integrated photocurrent
read-out.