Resonant enhancement of third-order nonlinear optical susceptibilities of Cd-free chalcopyrite nanocrystals within quantum confinement regime

摘要

Third-order nonlinear optical susceptibilities (X~(3) ) have been investigated for chalcopyrite CuInS_2 and AgInS_2 nanocrystals within a strong confinement regime. The imaginary part of X~(3) (ImX~(3))) of 2.0- and 4.9-nm-sized CuInS_2 nanocrystals and 2.6- and 4.3-nm-sized AgInS_2 nanocrystals are negative and exhibit resonant enhancement around the absorption between the highest quantized levels of valence band and the lowest conduction band due to the state-filling effect. Figure of merit of |ImX~(3)| ranges 10~(-20)-10~(-19)m~3/V~2, which is comparable to those of CdSSe nanocrystals.