DNA, sugars, and proteins at work in optics

In this Keynote presentation, we will review the use of selected biosystems in relevant optical applications: Complementary DNA strands can be used to put chromophore couples, e.g. for energy transfer between donor and acceptor, at a desired distance. By using the appropriate oligonucleotide length, we have spaced donor and acceptor at the Forster distance to show the influence of a carefully designed photonic bandgap on the Forster resonant energy transfer (FRET) efficiency. Amylose can be used to optimize the conformation of extended chromophores. Long conjugated systems show enhanced optical properties, but only in the all-trans conformation. This unlikely situation has been enforced by including the elongated molecule as a guest in the amylose host. The theoretically predicted enhancement in nonlinear optical polarizability, linear with conjugation length, has been demonstrated, but only when the chromophore was in the amylose. Fluorescent proteins can be used in cellular imaging. We will focus on the recent development (by genetic engineering) and characterization (by hyper-Rayleigh scattering) of fluorescent proteins for combined multiphoton fluorescence and second harmonic imaging. A small rainbow of fluorescent proteins has been characterized for their nonlinear optical properties.