Below band-gap nonlinear optical properties of semiconductor-doped glasses

Through nonlinear transmission and wave-mixing measurements, combined with structural data from neutron scattering, we obtain the below band-gap third-order susceptibility chi((3)) (both imaginary and real part) and the refractive-index-change per carrier of semiconductor nanocrystals embedded in a glass matrix. Our data covers a range of crystal radii between 2 and 14 nm and a range of ratios y = E(g)/(<(h)over bar omega>), where E(g) is the energy gap of the semiconductor and <(h)over bar omega> is the energy of the incident photon, between 1.1 and 1.9. The magnitude of chi((3)) and its dependence on y are comparable to those of related bulk semiconductors.