Second order hyperpolarizability of a polypeptide α-helix: Poly-γ-benzyl-L glutamate

Abstract

We have measured the second order β and third order γ hyperpolarizabilities of the PBLG polypeptide α‐helix and find it to have an extremely large nonlinearity. The decay time of the generated harmonic has been directly determined and found to be τ=5.0 msec which is consistent with Kerr and dielectric experiments. The nonlinear saturation at large static fields has been observed and is in quantitative agreement with theory.