Nonlinear absorption and refraction of quantum confined InP nanocrystals grown in porous glass

摘要

Single-beam Z-scan experiments have been used to measure the two-photon absorption coefficient β and bound electronic nonlinear refractive index γ of composites of InP nanocrystals grown in 40 and 150 A Vycor porous glass. These materials were also studied with two-beam time-resolved Z scans to confirm that the nonlinearities are instantaneous with respect to the ～100 ps pulses used. The magnitudes of the nonlinearities in the 150 A sample are found to be similar to those of bulk InP when scaled by the volume fraction of deposited material. For the 40 A sample the ratio γ/β is enhanced by a factor of fourteen compared to bulk InP.