Onto Innovation Inc.
VORTEX POLARIMETER

Abstract:

An optical metrology device uses a multi-wavelength beam of light that has azimuthally varying polarization states and/or phase states, referred to as a vortex beam. The metrology device focuses the vortex beam on a sample under test over a large range of angles of incidence. The metrology device may detect an image of the vortex beam reflected from the sample and measure the polarization state of the return light as function of the angle of incidence and the azimuth angle, which may be further measured at a plurality of different wavelengths. The vortex beam includes azimuthally varying polarization states, thereby enabling measurement of all desired polarization states without requiring the use of moving optical components. The polarization state information detected over multiple angles of incidence and wavelengths provides data with which an accurate determination of one or more characteristics of a sample may be determined.