A modulated reflectance measurement system includes two lasers for generating a probe beam and an intensity modulated pump beam. The probe beam is in the visible spectrum and the pump beam is in the ultra-violet spectrum. The pump and probe beams are joined into a collinear beam and focused by an objective lens onto a sample. Reflected energy returns through the objective and is redirected by a beam splitter to a detector. A lock-in amplifier converts the output of the detector to produce quadrature (Q) and in-phase (I) signals for analysis. A processor uses the Q and/or I signals to analyze the sample.