High-Q nanomechanical resonators are the building blocks of quantum optomechanics experiments, enabling the use of light to probe and manipulate mechanical motion at the quantum limit. This project will explore a new landscape in quantum optomechanics opened by the recent discovery of ultra-high-Q torsion nanoresonators, addressing both fundamental and applied research opportunities. A key goal is to start a dialogue between Quantum Imaging and Quantum Optomechanics fields which share common interests but have developed in parallel as subfields of Quantum Photonics and Quantum Optics. Another goal is to extend nanomechanical sensing to gravimetry, giving access to broad applications from inertial navigation to subterranean imaging. In addition to research, the principal investigator will develop a laboratory course for the Quantum Information Science and Engineering master?s program at University of Arizona. Spanning techniques from single-photon detection to dilution refrigeration, the course will answer a growing demand for hands-on experience in the quantum workforce. The research program has three thrusts, each based on reflecting a laser field from a strained silicon nitride nanoribbon possessing high Q torsion modes. First, a new field of imaging-based quantum optomechanics will be explored, with traditional interferometric measurement replaced by laser deflectometry (the optical lever method). A key goal is to observe radiation pressure shot noise in torque and study its influence on the quantum state of the reflected light field. Second, a compact pendulum gravimeter will be developed based on frequency tracking of a mass-loaded nanoribbon. The goal is a self-calibrated gravimeter with nano-g sensitivity in a chip-scale, arrayable format. Third, using advanced engineering techniques, nanoribbons with torsional quality factors exceeding 1 billion will be developed. Combined with quantum-limited deflectometry, an attempt will be made to ground state cool a nanomechanical oscillator from room temperature, of interest for both quantum technology and as a teaching tool. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.