Ultrastructure of light-harvesting compexes determined with second- and third-harmonic Stokes-Mueller polarimetric microscopy

Virginijus Barzdaa,c, Danielle Tokarzb,c, Gang Zhengd, Richard Ciseka,c
aDepartment of Physics; bDepartment of Chemistry; cDepartment of Chemical and Physical Sciences; dDepartment of Medical Biophysics University of Toronto, Canada

Due to high second- and third-order hyperpolarizabilities of photosynthetic pigments strong harmonic signals can be generated in crystalline pigment aggregates and pigment-protein complexes [1,2]. Therefore, the light-harvesting antenna complexes can be visualized with second harmonic generation (SHG) and third harmonic generation (THG) microscopy [2]. For example, Fig 1 shows SHG and THG images of chlorosomes. Nonlinear Stokes-Mueller polarimetric microscopy can be applied for studying pigment organization in crystalline light-harvesting complexes including chlorosomes and aggregates of light-harvesting pigment-protein complexes of photosystem II (LHCII). The novel double and triple Stokes-Mueller polarimetric microscopy [3] will be introduced and applications of pigment organization study in light-harvesting pigment-protein complexes will be presented.

Fig. 1 Second harmonic generation (SHG) and third harmonic generation (THG) microscopy images of chlorosomes. Scan area is 100x100 microns. Numbers indicate maximum photon counts per pixel.


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[2] R. Cisek, T. L. Spencer, N. Prent, D. Zigmantas, G. S. Espie and V. Barzda, Photosynthesis Research 2009, 102, 111-141.
[3] M. Samim, S. Krouglov and V. Barzda, Physical Review A 2016, 93, 013847-1-6