Sensitivity increase for coating thickness determination using THz waveguides.
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.
Theuer
M
M
1Oklahoma State University, School of Electrical & Computer Engineering, Stillwater, OK 74078, USA.
Beigang
R
R
Grischkowsky
D
D
D000327:Adsorption; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D012031:Refractometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055068:Terahertz Spectroscopy / Q000295:instrumentation*