Second harmonic generation (SHG), a label free imaging technique, which arises from non-centrosymmetric structures and the SH intensity depends on the relative orientation between the polarization of the incoming light and the second-order hyperpolarizability of the sample. Going beyond intensity measurements, SHG polarimetry can provide an interesting modality to probe the absolute molecular structure. The full polarization state of the polarized component cannot be found due to an ambiguity over the phase difference between the two measured polarization basis vectors. In contrast, the full...

Siliceous frustules were extracted from a representative fresh water diatom species (Cyclotella sp.) by treating with aqueous hydrochloric (HCl) acid. The structural characterizations of cleaned frustules were examined by scanning electron microscope (SEM). The microscopy images showed that the diatoms have a regular circular shape and are of almost equal size (average length is 9μm and average width is 3 μm).It was observed that the frustules were composed mostly of silica (~87 at %), and metal oxides (~11.5 at %) as found from FT-IR and EDX measurements. Optical emission showed clear...