DNA‐Based Polymers as Chiral Templates for Second‐Order Nonlinear Optical Materials |
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Authors: | Duangporn Wanapun Victoria J Hall Nathan J Begue James G Grote Dr Garth J Simpson Prof |
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Institution: | 1. Department of Chemistry, Purdue University, West Lafayette IN 47907 (USA), Fax: (+1)?765‐494‐0239;2. U.S. Air Force Research Laboratory, Dayton, Ohio 45324 (USA) |
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Abstract: | The unique symmetry properties of chiral systems allow the emergence of coherent second harmonic generation in polymeric materials lacking polar order. Deoxyribonucleic acid (DNA) treated with the surfactant cetyltrimethylammonium (CTMA) was drop‐cast to spontaneously form films that are active for coherent second harmonic generation (SHG). SHG images acquired as a function of incident and exigent polarization are in good agreement with theoretical predictions assuming nonpolar D∞ symmetry for the double‐stranded DNA chains. Doping the DNA films with crystal violet substantially increases the efficiency of SHG, but does not significantly alter the polarization‐dependence, suggesting that the SHG generated upon doping arises from the same chiral‐specific origin, presumably templated by the DNA. These results raise the possibility of new design strategies for organic nonlinear optical materials based on soft chiral polymers that do not require polar order. |
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Keywords: | chirality DNA optoelectronics polymers second harmonic generation |
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