Strong multiphoton absorption in chiral CdSe/CdS dot/rod nanocrystal-doped poly(vinyl alcohol) films

Cysteine-capped cadmium selenide/cadmium sulfide (CdSe/CdS) dot/rod nanocrystals (NCs) were synthesized and then doped in poly(vinyl alcohol) (PVA) films. Compared with an L-/D-cysteine-capped NC solution (10−4), the anisotropic factors of the circular dichroism and circular polarized luminescence in the doped PVA films increased by one order of magnitude, probably because of the enhanced anisotropy degree, crystal orientations, and ordered morphologies. The two- and three-photon absorption coefficients of the doped PVA films were determined as 0.58 cm/GW at 800 nm and 2.3×10−4  cm3/GW2 at 1300 nm, respectively. The chiral NC-doped PVA films are promising for applications in chirality-related nonlinear photonic devices.