A Widely Tunable Refractive Index in a Nanolayered Photonic Material

A class of composite polymer films is described in which the refractive index can be varied by simple mechanical forces. The films are comprised of 1024 alternating layers of an elastomer and a glassy polymer. When the layer spacing is much less than the wavelength of the probe light, these materials behave as effective medium composites. The layer thickness of the elastomer component and thus the effective index of the composite can be varied by compressing the composite.