Patent ID: 8059272

Claim:
A device, comprising: a light dispersing element dispersing electromagnetic radiation perpendicular to an axis defined by the light dispersing element; and a slit element, the slit element having a slit for exposure to electromagnetic radiation, wherein the slit element is configured and disposed for turning the slit between at least two positions with respect to the axis defined by the light dispersing element such that each of a corresponding at least two portions of the electromagnetic radiation pass through the slit when the slit is in each of the corresponding at least two positions, wherein the slit element is arranged such that each of the corresponding at least two portions of the electromagnetic radiation that pass through the slit travels along an optical axis and is dispersed by the light dispersing element after passing through the slit, wherein the corresponding at least two portions of the electromagnetic radiation are transferred from the slit to the light dispersing element without any relative rotation around the optical axis between the corresponding at least two portions of the electromagnetic radiation.