Combined terahertz spectral imaging and NIR Raman microscopy for the analysis of chromoprotein and chromophore films

A tunable frequency terahertz (THz) wave source provides spectral images of chromoprotein and chromophore films on quartz plates. A near-infrared (NIR) Raman microprobe mapping technique is used to measure the same regions in the films in order to detect the molecular structure and to understand THz spectral images. The fact that there is little fluorescence interference in NIR Raman microscopy for the colour films is an advantage over visible Raman microscopy. A combination of THz spectral imaging and NIR Raman microscopy techniques enables us to observe the distribution of molecules and to expand the field of THz imaging research.