Wavelength dependence and figures of merit of ultrafast third-order optical nonlinearity of a conjugated 3,3′-bipyridine derivative

摘要

The wavelength dependence and figures of merit of the third-order optical nonlinearity of a conjugated 3,3′-bipyridine derivative, a designed nondipolar structure of the donor-acceptor-acceptor-donor type, are reported. Z scans reveal positive nonlinear refractive-index changes for wavelengths longer than the one-photon absorption wavelength. Although the value of nonlinear Kerr coefficient n_(2) decreases from 6.0(±0.2)×10~(-6) cm~(2)/GW at 750 nm to 4.6(±0.7)×10~(-6) cm~(2)/GW at 1550 nm, the value of nonlinear absorption β decreases from 0.084 cm/GW at 750 nm to a negligible value at 1550 nm, giving rise to excellent nonlinearity-to-loss figures of merit at telecommunications wavelengths.