Results presented in this paper demonstrate that photo-modulated spectroscopic ellipsometry (PSE) can provide real-time information on electric field and composition without observation of FKO oscillations. Comparison with PR and PSE at the E-0 critical point (CP) in GaAs shows that electric field information can be obtained from PSE spectra measured at E-1 using simple amplitude considerations. Si1-xGex compositions (0.14 < x < 0.24) evaluated from Lorentzian fits to the E-1 PSE spectra also agree well with those obtained from PR. Reproducible PSE spectra have been obtained from, and simultaneous with. SE spectra in as little as 1 s from both Si and III-V semiconductors. Crown