2 ng/√Hz-resolution optomechanical accelerometer employing a three-dimensional MEMS interferometer
Cheng Li, Bo Yang, Xiang Zheng, Xin Guo, Zhenyu Sun, Luqiang Zhou, Xin Huang
Abstract
A portable and high-resolution optomechanical accelerometer employing a deformable grating-based micro-electro-mechanical system (MEMS) interferometer is presented in this Letter. The movable reflective mirror of this interferometer is realized by a low-frequency vertical sensing structure with a three-dimensional (3D)-spring construction, which, to the best of our knowledge, is first proposed and fabricated in this work. All the components of the sensor are packaged in a metal case with a compact size of 4 cm×6 cm×3.15 cm. The micrometer-scale springs permit the device to have a high mechanical sensitivity of 893.23 µm/ g and a resultant self-noise below 2 n <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>g</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:msqrt> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">H</mml:mi> <mml:mi mathvariant="normal">z</mml:mi> </mml:mrow> </mml:msqrt> </mml:math> from 2 to 7 Hz. Meanwhile, the measured voltage responsivity is as high as 15,874 V/ g , demonstrating it is one of the most sensitive accelerometers reported to date.