Optomechanical accelerometers for geodesy

Gravitational acceleration provides unique measurement opportunities to identify natural and man-made phenomena at global scales with signatures that are extremely difficult to mask due to their nature. Such gravitational observations are currently conducted with commercial gravimeters and gravity gradiometers that consist of complex mechanical structures operating large, inertially sensitive test masses and cumbersome displacement readout systems.

We are currently developing highly compact, portable, and cost-effective optomechanical inertial sensors of high sensitivity, building upon recent advances in the area of optomechanics. These technologies consist of low loss and highly stable monolithic mechanical oscillators that we combine with miniaturized laser interferometric displacement sensors, enabling us to achieve extremely high performances in acceleration sensing in small form factors.

To this end, it is necessary to develop various subsystems that are building blocks, each contributing to the implementation of these kinds of instruments. We will discuss our work on the fabrication of low-loss mechanical resonators, and the development of compact monolithic laser interferometer heads, fiber-based multi-color fiber interferometers, and new measurement concepts targeting smaller footprints and higher integration into photonic platforms. We will primarily report on the progress of our novel low-frequency optomechanical accelerometers for geodesy.