Research on a novel high sensitivity MOEMS deformable nano-grating accelerometer

摘要

With the development of the military field, there is growing interest in extremely high sensitivity. For meeting this desire,we design a novel high sensitivity MOEMS (Micro-Opto-Electro-Mechanical-System) accelerometer which is based onlaterally deformable nano-grating. Calculations predict that this sensitivity could be improved by up to two orders of magnitude in future design and it can reach as high as leg. These sensors consist of two offset layers of sub-wavelength polysilicon nano-gratings. They modulate the near-field intensity and polarization of an incident light source in response to relative motion of the nano-gratings. The reflected/transmitted optical beam intensity from the nano-gratings is measured as a function of the relative lateral positions of the nano-gratings. By using rigorous coupled-wave analysis (RCWA) and Fourier transform methods, we research the theory mechanism about nano-grating accelerometer. The accelerometer belongs to displacement sensors. For small changes in the spacing of the grating elements, a large change in the optical reflection and transmission amplitude observed. An in-plane motion detection sensitivity of 160fm/has been measured, and its displacement sensitivities will be as low as 12fm/mg. This sensitivity compares favorably to that of any other MEMS (Micro-Electro-Mechanical-System) transducer.