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<div align="center"><font face="Times New Roman"
color="#000000"><b>Seminar on</b></font></div>
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<div align="center"><font face="Times New Roman"
color="#000000"><b>Modern Optics and Spectroscopy</b></font></div>
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<div align="center"><font face="Arial" color="#000000"><b>Applications
of dynamically-tuned photonic structures</b></font></div>
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<div align="center"><font face="Times New Roman"
color="#000000"><b>Michelle Povinelli</b>,</font></div>
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color="#000000">University of Southern California</font></div>
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<div align="center"><font face="Times New Roman"
color="#000000">Tuesday, December 8, 2009</font></div>
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<div align="center"><font face="Times New Roman" color="#000000">12:00
- 1:00 p.m.</font></div>
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<div align="center"><font face="Times" color="#000000">The last decade
has seen great progress in the development of microphotonic devices
including integrated microphotonic waveguides, photonic crystals, and
microresonators. Integration of such devices on to semiconductor chips
has yielded so-called "microphotonic circuits" for insertion into
optical communication systems. A critical challenge for future
development of these technologies is the introduction and refinement
of mechanisms for tuning and dynamically reconfiguring microphotonic
circuits. Dynamically-tunable photonic structures will allow greatly
enhanced capabilities for optical information processing. In the
first part of talk, we discuss how optical forces can be used to
dynamically reconfigure photonic devices. We show that for silicon
microcantilever waveguides, optical forces can be used to design
highly-tunable birefringent behavior and compact polarization rotation
devices. For coupled photonic-crystal slabs, we show that optical
forces are strongly enhanced by guided resonance states and can result
in step-like relative motion. Such structures enable the enhancement
of light pressure over large areas in a configuration accessible to
free-space optical beams. In the second part of the talk, we discuss
applications of dynamic refractive index tuning for trapping and
storing light pulses. We present an optimal tuning scheme for slowing,
storing, and releasing light pulses in pairs of photonic-crystal
microcavities.</font></div>
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<div align="center"><font face="Times New Roman" color="#000000">Grier
Room, MIT Bldg 34-401</font></div>
<div align="center"><font face="Times New Roman"
color="#000000">Refreshments served after the lecture</font></div>
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