A tip-tilt-piston electrothermal micromirror array with integrated position sensors.

Area of Science:

• MEMS (Micro-Electro-Mechanical Systems)
• Optoelectronics
• Nanotechnology

Background:

• Micromirror arrays are crucial for optical systems, but thermal crosstalk and limited scan ranges pose challenges.
• Accurate position sensing is essential for controlling micromirror performance.

Purpose of the Study:

• To design and fabricate a 3x3 electrothermal micromirror array (MMA) with integrated temperature field-based position sensors.
• To evaluate the performance, including scan range, dynamic response, and thermal crosstalk, of the fabricated MMA.
• To validate the effectiveness of embedded thermal isolation structures.

Main Methods:

• Fabrication of a 3x3 electrothermal micromirror array with octagonal mirror plates (1.6mm x 1.6mm).
• Integration of temperature field-based position sensors for piston and tip-tilt detection.
• Implementation of thermal isolation structures to minimize thermal coupling between units.
• Experimental characterization of scan range, dynamic performance (rise/fall times), sensor sensitivity, and thermal crosstalk.

Main Results:

• Achieved a piston scan range of 218 μm and a tip-tilt optical scan angle of 21° at 5 Vdc per micromirror.
• Demonstrated good dynamic performance with rise time of 51.2 ms and fall time of 53.6 ms.
• On-chip sensors showed high sensitivity (1.5 mV/μm for piston, 8.8 mV/° for tip-tilt) across the full mirror movement range.
• Experimental study confirmed reduced thermal crosstalk due to embedded isolation structures.

Conclusions:

• The developed 3x3 electrothermal micromirror array with integrated sensors offers significant piston and tip-tilt capabilities.
• The embedded thermal isolation structures effectively mitigate thermal crosstalk, enhancing operational stability.
• The device shows promise for advanced optical applications requiring precise mirror control.