Patent ID: 7304792

Claim:
A system comprising: substantially planar mirror ( 4 ); convex spherical mirror ( 10 ); first concave spherical mirror ( 5 ); second concave spherical mirror ( 5 ′); and aberration correction system (CL); such that in use substantially planar mirror ( 4 ) directs a beam of electromagnetic radiation ( 3 ) to reflect therefrom and proceed as beam (IB) to reflect from convex spherical mirror ( 10 ), to first concave spherical mirror ( 5 ) which focuses it, as incident beam ( 6 ) to a spot (M) on sample (P), reflected electromagnetic radiation ( 7 ) from said spot (M) on said sample (P) being collected by second concave spherical mirror ( 5 ′), which reflectively directs it to reflect from convex spherical mirror ( 10 ) and emerge as output beam (OB); said aberration correction system (CL) being positioned so that both input (IB) and output (OB) beams pass therethrough; said substantially planar mirror ( 4 ) being movable so as to enable said beam of electromagnetic radiation ( 3 ) to be directed toward said convex spherical mirror ( 10 ) at different locations thereon, such that said beam of electromagnetic radiation ( 3 ) approaches the same spot (M) on said sample (P) at determinable angles-of-incidence.