Abstract
Second Harmonic Scattering is the incoherent second order light scattering occuring in isotropic bulk solutions due to the molecular orientation. It is an efficient technique to determine the molecular second order polarizability of solute molecules. The measurement of the bacteriorhodopsin protein hyperpolarizability has opened the way to the determination of the non linear response of biomolecules. Since then, many different proteins have been investigated.In addition to their technological promess, the biological and chemical properties of DNA, and the almost infinite variety of structures that can be obtained, the DNA structures are considering for many applications, in biology and biophysics, to study biomaterials and reproduce cellular behaviors, but also in optoelectronics, to modify optical properties of surfaces, or finally as micrometric molecular motors.DNA nucleotides, are demonstrating to be versatile materials in natural electronics and photonics, a very promising field of research in which biological materials are employed to build environmentally friendly microelectronic and optoelectronic devices.It has to be noted that there are much fewer reports describing the use of nucleobases in bioelectronics than for DNA. The measurements of the first hyperpolarizability allow for the characterization of the solute quadratic optical nonlinear response can yield information about the macromolecular conformation in solution. Particularly, the angular dependence of the HRS intensity allowed to unravel further information on the nonlinear response symmetry.Beyond nucleotides, many of non-canonical DNA structures have shown their involvement in diseases like cancer and genetic disorders remain of interest and the present work constitutes a first step into this direction.Hence, we present the studies of biological materials in reporting the measurement of the first hyperpolarizability of the four DNA nucleotides and compare them to the results of DFT calculations. A polarization analysis of the HRS intensity was also performed to question the symmetry of the first hyperpolarizability tensor.