Polarization converting unit, illumination optical system, exposure apparatus, and device manufacturing method

摘要: According to one embodiment, a polarization converting unit, for incident light into in predetermined state and emitting the converted light, has first optically rotatory member having thickness distribution of thicknesses an optical-axis direction different at plurality locations second distribution, each which is rotate linearly polarized thereto as propagating around direction. The members are comprised optical material with activity arranged so have crystal axis coincident or parallel Particularly, sum respective superimposed regions from other when viewed along