Abstract
We present experimental results which demonstrate that the effective third-order susceptibility of a composite optical material can exceed those of the materials from which it is constructed. In particular, we have formed a composite of alternating, sub-wavelength-thick layers of titanium dioxide and the conjugated polymer poly( -phenylene-benzobisthiazole), and find that its nonlinear susceptibility exceeds that of its more nonlinear constituent by 35%. The enhancement of the nonlinear susceptibility, which under more ideal but still realistic conditions can be as large as a factor of 10, can be understood as a consequence of local field corrections.
- Received 24 October 1994
DOI:https://doi.org/10.1103/PhysRevLett.74.1871
©1995 American Physical Society