Design of out-of-plane MOEMS accelerometer with subwavelength gratings

A novel out-of-plane MOEMS accelerometer based on near-field evanescent wave coupling by means of variable period subwavelength gratings has been proposed. First, the diffraction order number was calculated. Then, structure parameters were optimized by finite element analysis to achieve high sensitivity in an ideal vibration mode. Results show that the accelerometer has displacement sensitivity at 2033 nm/G with a measurement range of 0.12 G, corresponding to first diffraction beam optical sensitivity 0.46%/mG. Finally, we designed the fabrication method to form such MOEMS accelerometer and successfully fabricated the uniform and well-designed subwavelength gratings with the period of 1.0 μm by FIB/SEM dual beam system. The subwavelength gratings fabricated are very close to those designed within the experimental error to lay the foundation for the subsequent fabrication. These results provide a theoretical basis for design and fabrication of an out-of-plane MOEMS accelerometer with subwavelength gratings.