Sensitivity increase for coating thickness determination using THz waveguides

M. Theuer, R. Beigang, D. Grischkowsky
2010 Optics Express  
We report on layer thickness determination down to a thickness of 2.5 microns using terahertz waveguide spectroscopy. Compared to typical single-pass transmission measurements in the time domain, the effective THz pulse delay is considerably increased for a given layer thickness by using the high filling factor of the THz waveguide. This corresponds to a sensitivity increase up to a factor of 50 for the measured delay, allowing the direct measurement of layer thicknesses down to below hundredths of a THz wavelength.
doi:10.1364/oe.18.011456 pmid:20589006 fatcat:3py7z7ftfvhvdnqeun2vahs7yq