Highly sensitive lateral deformable optical MEMS displacement sensor: anomalous diffraction studied by rigorous coupled-wave analysis

This paper discusses the pulse signal of a highly sensitive lateral deformable optical microelectromechanical systems (MEMS) displacement sensor based on Wood's anomalies and its corresponding tolerance. The optical reflection amplitude of the device changes with the displacement of the nanostr...

Full description

Saved in:
Bibliographic Details
Published in:Applied optics (2004) 2015-10, Vol.54 (30), p.8935-8943
Main Authors: Wang, Chen, Lu, Qianbo, Bai, Jian, Yang, Guoguang, Wang, Kaiwei, Liu, Dong, Yang, Yongying
Format: Article
Language:English
Subjects:
Devices
Displacement
Formability
Gratings (spectra)
Microelectromechanical systems
Noise levels
Slopes
Wavelengths
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This paper discusses the pulse signal of a highly sensitive lateral deformable optical microelectromechanical systems (MEMS) displacement sensor based on Wood's anomalies and its corresponding tolerance. The optical reflection amplitude of the device changes with the displacement of the nanostructured grating elements. Unexpectedly, the device's original sinusoidal signal develops into a new signal form (i.e., a pulse signal), when the air gap between the two layers of gratings decreases. Since the slope of the pulse signal, namely 2.5%/nm (i.e., 0.65 dB/nm), is eight times higher than that of the original signal form, namely 0.3%/nm (i.e., 0.03 dB/nm), the sensitivity of the structure improves by eight times. However, this device is very sensitive to parameters such as its wavelength, period, duty ratio, and air gap. In this paper we used rigorous coupled wavelength analysis (RCWA) to analyze and optimize the respective influence of each parameter on the device's performance. We have introduced two methods to search for the optimal setting and have demonstrated the optimal settings of different incident lights. The simulation results indicate that it is close to 85% possible to achieve an actual device with the highest slope superior to 0.5%/nm and it is 64% possible that the highest slope of an actual device falls in the interval ranging from 1.0%/nm to 2.0%/nm. All the simulated data helped us better understand the tolerance of the pulse signal and guide us toward the development of an actual device.
ISSN:1559-128X
2155-3165
DOI:10.1364/AO.54.008935