In-Plane Nano-G Accelerometer Based on an Optical Resonant Detection System

We have successfully demonstrated a series of results that push the limits of optical sensing, acceleration sensing and lithography. We previously built some of the most sensitive displacement sensors with displacement sensitivities as low as 12 fin/radicHz at 1 kHz. Using reference detection circuitry in conjunction with correlated double sampling methods, we have lowered the 1/f noise floor to 10 milli-Hz, hence improving the detection limit at low frequencies (10 milli-Hz) from 37 pm/radicHz to 50 fm/radicHz i.e. by 57.3 dB. We have developed the capability to convert these highly sensitive displacement sensors to highly sensitive acceleration sensors through innovative low-stress mass addition and direct mass integration processes. We have built accelerometers with resonant frequencies as low as 43 Hz and thermal noise floors as low as 10 nG/radicHz. We have pushed the limits of shaker table experiments to verify direct acceleration measurements as low as 10 muG/radicHz.