Elliptical Nanowire Optics

Nanostructured materials modulate the phase of optical waves traveling through them. When the nanostructure geometry is anisotropic, different polarizations of light interact differently, an effect called form birefringence. Recently, we demonstrated that elliptical cross-section nanowires are an extremely high resolution method to locally control form birefringence.

Array of 1 mm tall elliptical silicon nanowires on a 250 nm pitch

A two dimensional grating designed to deflect horizontally polarized light vertically, and vertically polarized light horizontally

Using form birefringence, two optical functions can be encoded into the same physical aperture. This can be used to tune the properties of imaging systems.

Zoom lens: Different polarizations have different focal lengths, projecting two images with different magnifications.

Stereoscopic lens: Different polarizations have a different optical axes, projecting two images from different perspectives.

E. Schonbrun, K. Seo, and K. B. Crozier, "Reconfigurable imaging systems using elliptical nanowires," Nano Lett., 11, 4299-4303 (2011).
E. Schonbrun, "Nanowire lenses can perform two functions at once," SPIE Newsroom, 6 January 2012.