Figure 6. UMARS of hidden object; (a) 1^st layer Ammonium Nitrate (AN), 2^nd layer t-Stilbene (TS) concealed inside AN, (b) Schematic representation of illumination and collection of Raman spectra from different slices of the cylindrical glass vial, (c) Raman signal of the bilayer sample at different heights, and (d) Raman intensity variation of AN & TS as a function of height.

Vertical step size 5 mm. Spectral acquisition time 500 s.