An optical inspector includes a radiating source, a time varying beam reflector, a telecentric scan lens, a first waveplate, a second waveplate, a polarizing beam splitter, and a detector. The radiating source irradiates the first waveplate with a linearly polarized source beam generating a circularly polarized source beam, which irradiates a first position of on the time varying beam reflector. The time varying beam reflector directs the source beam to the telecentric scan lens, which in turn directs the source beam to a transparent sample. The reflected radiation from the transparent sample is directed via the telecentric lens and the time varying beam reflector to the second waveplate, which converts circularly polarized reflected radiation to linearly polarized reflected radiation including radiation that is vertically polarized and radiation that is horizontally polarized. The polarizing beam splitter redirects vertically polarized reflected radiation to the detector while horizontally polarized reflected radiation passes through.