Abstract: Apparatus for imaging a surface, including an acousto-optic (AO) system. The AO system includes an AO element having a radiation input surface and a radiation output surface. The element is configured to receive radio-frequency (RF) pulses and a radiation input at the radiation input surface and to generate traveling beams from the radiation output surface. The AO system also includes an inhomogeneous polarization generator, positioned relative to the AO element so that the AO system outputs traveling inhomogeneously polarized beams. The apparatus includes objective optics which are configured to focus the inhomogeneously polarized beams onto the surface so as to form respective traveling spots thereon; collection optics, which are configured to collect scattered radiation from the traveling spots and to focus the scattered radiation to form respective image spots; and a detector which is arranged to receive the respective image spots and to generate a signal in response thereto.

Abstract: A method for characterizing a surface, consisting of dividing the surface into pixels which are characterized by a parameter variation and defining blocks of the surface as respective groups of the pixels. The pixels are irradiated in multiple scans over the surface with radiation having different first polarization states. At least part of the radiation returning from the pixels is analyzed using second polarization states, to generate processed returning radiation. For each scan, block signatures of the blocks are constructed using the processed returning radiation from the group of pixels in each block. Also for each scan, a block signature variation is determined using the respective block signatures of the blocks, and, in response to the block signature variation, one of the first polarization states and at least one of the second polarization states are selected for use in subsequent examination of a test object.

Abstract: Apparatus for imaging a surface, including an acousto-optic (AO) system. The AO system includes an AO element having a radiation input surface and a radiation output surface. The element is configured to receive radio-frequency (RF) pulses and a radiation input at the radiation input surface and to generate traveling beams from the radiation output surface. The AO system also includes an inhomogeneous polarization generator, positioned relative to the AO element so that the AO system outputs traveling inhomogeneously polarized beams. The apparatus includes objective optics which are configured to focus the inhomogeneously polarized beams onto the surface so as to form respective traveling spots thereon; collection optics, which are configured to collect scattered radiation from the traveling spots and to focus the scattered radiation to form respective image spots; and a detector which is arranged to receive the respective image spots and to generate a signal in response thereto.