We monitor the adsorptionofRhodamine 800, and the sedimentation of a polytetrafluoroethylene (PTFE) suspension at the surface of a fused-silica prism, by measuring both the absorption and s-p phase shift Δ of a 740 nm probe laser beam, using evanescent-wave cavity ringdown ellipsometry (EW-CRDE). The two systems demonstrate the complementary strengths of EW-CRDE, as the progress of adsorption of the Rhodamine 800 dye can only be observed sensitively via the measurement of absorption, whereas the progress of sedimentation of PTFE can only be observed sensitively via the measurement of Δ. We show that EW-CRDE provides a sensitive method for the measurement of Δ and demonstrates precision in Δ of about 10-4 deg.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Engineering (miscellaneous)
- Electrical and Electronic Engineering