Patent ID: 8896825

Claim:
An apparatus, comprising: a time varying beam reflector; a radiating source that irradiates a first position of the time varying beam reflector; a waveplate that is positioned between the radiating source and the time varying beam reflector; a telecentric lens that directs the radiation reflected by the time varying beam reflector onto a sample, wherein the radiation reflected by the time varying beam reflector and directed by the telecentric scan lens produces a moving irradiated spot on the sample, wherein the irradiation of the sample causes scattered radiation to reflect from a top surface of the sample and a bottom surface of the sample; a first lens that receives scattered radiation from the sample, wherein the first lens is orientated at an oblique angle to the plane of incidence of the moving irradiated spot on the transparent sample; a field stop located at the focal plane of the first lens, wherein the field stop blocks a first portion of the scattered radiation, and wherein a majority of the first portion of scattered radiation is reflected from one surface of the sample; a de-scan lens located after the focal plane of the first lens that receives a second portion of the scattered radiation not blocked by the field stop; and a detector located at the focal plane of the de-scan lens.