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Terahertz profilometry at 600 GHz with 0.5 microm depth resolution
Bernhard Hils1, Mark D Thomson, Torsten Löffler
1Physikalisches Institut, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt am Main, Germany. hils@physik.uni-frankfurt.de
Optics Express
|July 24, 2008
Summary
Terahertz (THz) radiation offers an alternative for measuring rough surfaces when visible light interferometry fails. Heterodyne profilometry at 600 GHz accurately determines surface topography, achieving 0.5 µm uncertainty.
Area of Science:
- Physics
- Optical Engineering
- Metrology
Background:
- Surface topography characterization is crucial for material science and engineering.
- Conventional interferometry methods using visible or near-infrared light are limited by surface roughness.
- Rough surfaces (on the scale of a tenth of the wavelength) pose challenges for optical metrology.
Purpose of the Study:
- To explore Terahertz (THz) radiation as an alternative for surface topography measurement.
- To demonstrate the efficacy of heterodyne profilometry in the THz regime.
- To achieve accurate surface topography determination for rough materials.
Main Methods:
- Utilized heterodyne profilometry technique.
- Employed Terahertz (THz) radiation at a frequency of 600 GHz.
- Developed a method for accurate surface topography measurement.
Main Results:
- Demonstrated successful application of THz heterodyne profilometry.
- Achieved accurate determination of surface topography.
- Obtained an expanded standard uncertainty of 0.5 µm for the measurements.
Conclusions:
- Terahertz (THz) radiation is a viable alternative for surface topography characterization of rough materials.
- Heterodyne profilometry at 600 GHz provides a precise method for metrology.
- The developed method offers high accuracy for challenging surface measurements.
