ABSTRACT
In three-dimensional (3D) optical elements, the wavefront is shaped throughout an entire
volume of modulated refractive index. We have devised a number of diffractive and
subwavelength 3D optical elements with unusual imaging capabilities. In the diffractive
regime, we have implemented such elements as volume holograms and shown that
multiplex volume-holographic pupils (MVPs) can be used for 3D fluorescence imaging.
Results from optical sectioning in phantoms and in vivo mouse tissue show optical
sectioning capability with 50μm longitudinal and <5μm lateral sampling distances and
good background noise rejection. In the subwavelength regime, we have worked on
theoretical modeling and fabrication of 3D optics. In the area of theoretical modeling, we
have shown that subwavelength 3D modulations can behave as gradient index (GRIN)
optical elements with arbitrary modulation of the refractive index. To assemble
subwavelength 3D optics, we devised a novel 3D nanomanufacturing and assembly
technique, Nanostructured Origami™, where the 3D structure is assembled by folding a
nanopatterned membrane. We show experimental results on sub-2μm folding and sub-
30nm alignment between folded layers. Some applications of Nanostructured Origami
outside Optics will also be discussed, such as a high-density MEMS supercapacitor, and a
cantilever based chemical sensor.

George Barbastathis is Associate Professor of Mechanical
Engineering at MIT. He received the Diploma in
Electrical and Computer Engineering from the National
Technical University of Athens in 1993, and the M.Sc.
and Ph.D. in Electrical Engineering from Caltech in 1994
and ’97, respectively. Between 1997-99 he was a Postdoctoral
Research Associate with the Beckman Institute
at the University of Illinois, Urbana-Champaign. Between
2006-2007 he was Visiting Scholar with the School of
Engineering and Applied Science at Harvard University.
Between 2008-2009 he is a Research Scientist with the
Singapore-MIT Alliance for Research and Technology
(SMART) Centre in Singapore. His research is centered on the physics and engineering
of 3D optical imaging systems based on volume holography and 3D nanostructures with
applications to optical imaging and metrology for biological, environmental, and energy
related applications.