UCLA

Accurate determination of attitude and position is a fundamental aspect of inertial navigation. Modern navigation techniques use a combination of sensors, that rely on an Inertial Measurement Unit (IMU) for short term position estimation and at least one constellation of the Global Navigation Satellite System (GNSS), such as the Global Positioning System (GPS), to reduce long term solution divergence. However, for earth and space applications, in GNSS denied environments, the performance of IMUs, and of their core accelerometers, is critical for the success of the mission. In fact, improvement in accelerometer’s bias stability and resolution can enable longer autonomous navigation vehicles, including satellites and spacecraft. At the same time, reductions in size and weight are key factors for longer range and extended mission duration.However, scaling down the dimensions of transducers that depend on their weight to harvest specific force is not an easy task, since reduction in mass is proportional to the cube of the length (~ l 3). A smaller transducer needs to be more sensitive to motional displacements, if it were to maintain the same performance, which translates into an operational point closer to the physical limits. In this regard, recent advances in radiation-pressure driven cavity optomechanics have provided new frontiers in laser cooling of mesoscopic systems, chip-scale stable RF sources, phonon lasers, and chaos. By coupling optical and mechanical modes, it is possible to detect tiny mechanical motions in the order of a few femtometers, which has attracted interest for sensing design on accelerometers and other transducers, and has enabled applications such as the detection of gravitational waves. In our work, we propose an optomechanical accelerometer that in contrast to state-of-the-art piezoelectric or capacitive accelerometers, offers an integrated feedback system and optical readout, which provides advantages like narrow-linewidth, high-sensitivity laser detection, with low-noise resonant optomechanical transduction close to the thermal limit, and can be used to measure atto-Newton level forces through detecting femtometer displacements. This technique will enable the development of more sensitive accelerometers and gravimeters that will improve position determination.