Polarimetric z-Scan Study of Nonlinear Chirooptic Properties of Chiral Polyfluorene

Chiral photonics is an emerging field which deals with enantioselective light-matter interactions, offering numerous exciting applications. Two main approaches to enhancing enantioselective interactions are currently under extensive study: 1) structuring light itself, and 2) developing materials with gigantic optical activity. Both are required to realize the full potential of this emerging field. Here, the intensity-dependent optical activity of a chiral polyfluorene film that has been studied by using open-and closed-aperture z-scan techniques with similar to 775 nm and similar to 160 fs laser pulses is reported. For a film of similar to 20 mu m thickness, the measured two-photon absorption coefficients are 1.24 and 1.49 cm GW(-1), respectively, and the nonlinear refractive indices are 8.74 x 10(-5) and 1.38 x 10(-4) cm(2) GW(-1) for right and left circularly polarized laser beams, respectively. The nonlinear optical activity of pure, undoped polyfluorene is the highest reported so far.