Optical Feedback for Sensitivity Enhancement in Direct Raman Detection of Liquids

Figure 2

(a) Intensity of the Raman-scattering spectrum as a function of Raman shift and depth of the “blocking” mirror below the liquid surface, where 6 Raman peaks can be observed. (b) The Raman signal peak intensity (I(z)) at about 895 cm⁻¹ varying with the depth (z) of the “blocking” mirror (black curve). Red curve: dI(z)/d(z), showing an inflection point roughly at the focus of the laser beam with z = 28 mm. Inset: schematic illustration of the experimental setup.

(a)

(b)