Two-axis asymmetric electrothermal MEMS micromirror for decoupled resonant scanning

Area of Science:

• Microelectromechanical Systems (MEMS)
• Optical Endomicroscopy
• Scanning Micromirrors

Background:

• Electrothermally-actuated MEMS micromirrors offer large scan ranges at low voltages for optical endomicroscopy.
• Axis coupling at resonance limits the performance of traditional symmetric designs.

Purpose of the Study:

• To propose and demonstrate an asymmetric MEMS micromirror design for decoupled two-axis resonant scanning.
• To overcome the challenge of inter-axis coupling in MEMS micromirrors for improved optical endomicroscopy.

Main Methods:

• Design and fabrication of an asymmetric two-axis electrothermal MEMS micromirror.
• Experimental characterization of scanning performance, including scan range, frame rate, and coupling.

Main Results:

• Successful fabrication of the asymmetric MEMS micromirror.
• Achieved a distortion-free Lissajous pattern with a frame rate of 30 fps and a field of view (FOV) > 21°×22°.
• Reduced inter-axis coupling by one order of magnitude compared to symmetric designs, operating at a low 2 Vpp.

Conclusions:

• The asymmetric design effectively decouples the two scanning axes, enabling high-speed, wide-FOV endoscopic imaging.
• The micromirror's performance is suitable for advanced medical imaging applications requiring safe driving voltages.
• This work presents a significant advancement for MEMS-based optical endomicroscopy systems.