Terahertz imaging via simultaneous surface and sub-surface evaluation via non-linear optical response

摘要

Methods, systems and apparatuses are disclosed for interrogating characteristics of a substrate material surface and sub-surface by evaluating: 1) sum frequency output beams produced by combining an optical source input and a Terahertz source input, and 2) Terahertz second harmonic frequency output from a Terahertz source input.

主权项

1. A method for evaluating a substrate material having a substrate material surface and a substrate material sub-surface comprising the steps of:
directing a first input beam comprising electromagnetic radiation onto a predetermined area of a substrate material having a substrate material surface and a substrate material sub-surface, the electromagnetic radiation of the first input beam having a wavelength of from about 1000 to about 300 nm; directing a second input beam comprising electromagnetic radiation onto the predetermined area of the substrate material surface, the electromagnetic radiation of the second input beam having a THz wavelength between about 0.3 mm and about 3 microns; mixing the first input beam and the second input beam at the substrate material surface to provide a sum frequency output beam; penetrating the substrate material surface to a predetermined depth of the substrate material sub-surface with the second input beam to provide a THz second harmonic output beam comprising a THz second harmonic signal of the second input beam; receiving the sum frequency output beam with a sum frequency output beam detector; receiving the THz second harmonic output beam with a THz second harmonic output beam detector; and measuring one or more characteristics of the substrate material sub-surface by evaluating the sum frequency output beam received by the sum frequency output beam detector.