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BEGIN:VEVENT
DTSTAMP:20261020T161629Z
LAST-MODIFIED:20160317T152835Z
DTSTART:20160323T140000Z
DTEND:20160323T150000Z
UID:event1580@bu.edu
URL:http://physics.bu.edu/internal/events/show/1580
SUMMARY:Statics and Dynamics of Electrothermal Micromirrors
DESCRIPTION:Featuring Jessica Morrison\n\nPart of the Departmental Seminars
	.\n\nDissertation Committee: David Bishop\, Tom Little\, David Campbell\, S
	hyam Erramilli\, John Butler\n\nAbstract:\n\nModern fabrication techniques 
	are enabling the adoption of microelectromechanical systems (MEMS) devices 
	in commodity applications never anticipated. Low-cost lighting systems can 
	exploit micromirrors both to enable directed or sculpted light and to suppo
	rt short-range optical communications. We have developed a novel MEMS mirro
	r\, an SEM image of which is shown in the figure. The mirror fully integrat
	es variable focus and dynamic beam steering providing unique advantages in 
	connected lighting systems.\n\nThe fabrication process is fixed by using a 
	commercial foundry process\, PolyMUMPs by MEMSCAP\, providing a reliable an
	d reproducible system that can be commercialized easily. The mirror uses el
	ectrothermal actuation to both steer the light and tune the focal length. R
	esidual stresses in the deposited layers during the fabrication process pro
	vide an initial curvature that projects the system from the substrate. The 
	curvature of a bimorph can be tuned using Joule heating. A large electrical
	 and thermal impedance mismatch allows independent heating of the mirror an
	d the bimorph legs. \n\nAn in-depth characterization of the dynamics of suc
	h a system provides insight into tunable mechanical properties such as the 
	resonant frequency and quality factor. The degenerate resonant modes can be
	 separated significantly. As a result\, the system can be scanned at increa
	singly large angles. In other words\, nonlinearities and coupled mechanical
	 modes allow variable damping and amplification.\n\n![Jessica](/resources/e
	vent-image/1580/8323f34_original)
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:TENTATIVE
CLASS:PUBLIC
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