TITLE: Phase-Synchronized Pulsed Microshutter Actuation for Spectroscopic MEMS Arrays

ABSTRACT: Microshutter arrays are critical for enabling high-contrast spectral imaging in applications such as astronomy, lidar, and hyperspectral sensing. By selectively transmitting light from specific spatial targets while blocking unwanted sources, these devices eliminate spectral overlap and improve signal-to-noise ratio. Traditional actuation methods for microshutters, such as magnetic or electrostatic pull-in, require high voltages (60–125 V), suffer from fabrication complexity, and present reliability issues in miniaturized or battery-powered systems. This thesis introduces a novel phase-synchronized pulsed actuation method that replaces conventional resonance-based pull-in with a direction-aware, cycle-specific pulsing scheme. Inspired by the analogy of pushing a swing only when it is moving in the correct direction and at the optimal location within its cycle, the proposed method applies brief, electrostatic pulses only when the shutter's motion satisfies a target positional and directional window. This approach avoids the phase drift problems that occur in traditional resonance pull-in as the electrostatic gap narrows and the system becomes increasingly nonlinear. It also eliminates the need for precise frequency tracking, making the method inherently robust to damping, variation in device parameters, and environmental drift. Mechanical modeling is performed using a one-dimensional mass-spring-damper system with a nonlinear electrostatic actuator. The new control strategy is simulated and compared against both quasi-static and resonance-based pull-in techniques. Results show that sub-5 V pulsed actuation reliably achieves shutter pull-in in under 20 milliseconds, with significantly reduced power requirements and improved timing robustness. A two-layer SOI micromachined structure is proposed, with flexure geometry enabling tailored dynamic responses for each shutter. Optical performance is validated through COMSOL simulations solving the Helmholtz equation, confirming that shutter displacement and alignment yield high transmission contrast in the visible to mid-infrared spectrum. This work demonstrates that phase-synchronized pulsed microshutter actuation offers a scalable, low-power, and fabrication-friendly alternative to traditional MEMS shutter control, with strong implications for miniaturized, programmable spectrometers in future mobile or space-based platforms.

MAJOR ADVISOR: Jason Clark V

MINOR ADVISOR: Vincent Immler
COMMITTEE: Harish Subbaraman
COMMITTEE: Larry Cheng
GCR: Oksana Ostroverkhova