Giant Birefringent Optics in Multilayer Polymer Mirrors
Michael F. Weber,
Carl A. Stover,
Larry R. Gilbert,
Timothy J. Nevitt,
Andrew J. Ouderkirk
*
Multilayer mirrors that maintain or increase their
reflectivity with increasing incidence angle can be constructed using
polymers that exhibit large birefringence in their indices of
refraction. The most important feature of these multilayer interference
stacks is the index difference in the thickness direction (z
axis) relative to the in-plane directions of the film. This
z-axis refractive index difference provides a variable that
determines the existence and value of the Brewster's angle at layer
interfaces, and it controls both the interfacial Fresnel reflection
coefficient and the phase relations that determine the optics of
multilayer stacks. These films can yield optical results that are
difficult or impossible to achieve with conventional multilayer optical
designs. The materials and processes necessary to fabricate such films
are amenable to large-scale manufacturing.
3M Film/Light Management Technology Center, 3M Center, St. Paul,
MN 55144, USA.
*
To whom correspondence should be addressed. E-mail:
3mopticalfilm{at}mmm.com
