Mechanical resonators based on stressed silicon nitride have both exemplary optical and me-
chanical properties. Tensioning the silicon nitride enhances the mechanical properties of these
devices owing to the phenomenon of dissipation dilution. The effects of dissipation dilution can be
further enhanced through geometric engineering of the device, which has yielded devices that are
capable of quantum operation in ambient conditions. At the same time, interferometric detection
allows for a quantum-limited readout of the mechanical motion of such devices. The mechanical
motion of these devices can be selectively influenced by external perturbations by augmentation of
the mechanical resonator. In this work, we design a variety of sensors utilizing this combination
of low dissipation, precise motional readout, and a near-universal coupling to an external field of
interest. In this work, we study each of these elements, as well as their interplay, as they pertain to
tensioned silicon nitride mechanical resonators. We study the ramifications of functionalization for
force sensors, with a specific focus on developing probes for external magnetism, acceleration, and
gravity. Such sensors could enable high-resolution spin imaging or inertial navigation, and moti-
vate geometries and probes for fundamental physics in the context of larger-scale masses. My work
presents the development of specific design criteria pertaining to force sensors based on phononic
crystal membrane resonators. A deeper study of these resonators leads to a generalized formal-
ism to understand the effects of a general, spatially varying, thermal environment on the sensing
performance of such devices. This formalism is verified by direct measurement of an engineered
micromechanical resonator exposed to a spatially varying thermal bath. The work concludes by
considering the development of a micromechanical bolometer based on frequency-shift detection in
engineered tensioned silicon nitride resonators.
N2 -Mechanical resonators based on stressed silicon nitride have both exemplary optical and me-
chanical properties. Tensioning the silicon nitride enhances the mechanical properties of these
devices owing to the phenomenon of dissipation dilution. The effects of dissipation dilution can be
further enhanced through geometric engineering of the device, which has yielded devices that are
capable of quantum operation in ambient conditions. At the same time, interferometric detection
allows for a quantum-limited readout of the mechanical motion of such devices. The mechanical
motion of these devices can be selectively influenced by external perturbations by augmentation of
the mechanical resonator. In this work, we design a variety of sensors utilizing this combination
of low dissipation, precise motional readout, and a near-universal coupling to an external field of
interest. In this work, we study each of these elements, as well as their interplay, as they pertain to
tensioned silicon nitride mechanical resonators. We study the ramifications of functionalization for
force sensors, with a specific focus on developing probes for external magnetism, acceleration, and
gravity. Such sensors could enable high-resolution spin imaging or inertial navigation, and moti-
vate geometries and probes for fundamental physics in the context of larger-scale masses. My work
presents the development of specific design criteria pertaining to force sensors based on phononic
crystal membrane resonators. A deeper study of these resonators leads to a generalized formal-
ism to understand the effects of a general, spatially varying, thermal environment on the sensing
performance of such devices. This formalism is verified by direct measurement of an engineered
micromechanical resonator exposed to a spatially varying thermal bath. The work concludes by
considering the development of a micromechanical bolometer based on frequency-shift detection in
engineered tensioned silicon nitride resonators.
PB - University of Colorado PY - 2023 TI - Designing sensors with tensioned silicon nitride micromechanical resonators ER -