An apparatus and method for spatially shifting a light using a multilayer
thin-film stack of at least two materials having unequal optical
properties, such as indices of refraction and absorption coefficients.
The apparatus has an input face for admitting the light into the
apparatus and an impedance matching mechanism for maximizing the
in-coupling of the light into the multilayer thin-film stack at a
non-normal incidence. The non-normal incidence is sufficient to generate
a spatial shift of the light in the multilayer thin-film stack as a
function of at least one light parameter, such as wavelength and/or
polarization of the light, thereby separating the light into light
components. The spatial shift is achieved by any one or any combination
of effects including superprism, turning point and energy confinement.
These effects are achieved in the multilayer thin-film stack by
appropriately engineering its layer sequence.