Optic for a total internal reflection (TIR) holographic system

The present invention relates to an optic, in particular for use as optic in a total internal reflection (TIR) holographic system, a TIR apparatus and a process using such an optic. The optic comprises a plate (23) which has essentially flat first and second surfaces. It is of a material being transparent for the light used in the lithographic process and has a periodic grating structure (25,37) on the first surface whose period, in relation to the incident angle and wavelength of the light and the refractive index of the plate material, is such that only a zeroth (33) and one first order beams (29) of the light (27) being incident on the first surface at a predetermined incident angle ( 4) are transmitted into the plate (23) and the transmitted first diffraction order (29) is essentially totally reflected at the second surface/air interface.