Refractive Index and Surface Relief Grating Formation in DNA Based Dye-Doped Films

摘要

The refractive index and surface relief grating formation in deoxyribonucleic (DNA) based thin films, functionalized with the well known fluorophore LDS698, was studied in holographic two beam coupling geometry and as function of the polarization of incident laser beams. The DNA biopolymer used was functionalized with cetyl-trimethylammonixim chloride (CTMA) surfactant. If both beams polarization are parallel (p-p) a refractive index grating is formed, as is usually observed, this is also the case when both beams polarizations are perpendicular (s-p). This fact is tentatively interpreted as due to the DNA matrix chirality. Also formation of a surface relief refractive index grating is observed in these materials for the first time, in contrary to earlier observations reported in literature. This effect is tentatively explained as due to the creation of an electrostatic bond between DNA and the guest molecules, which are electrically charged.