Degenerate four-wave mixing (DFWM) was used as a technique to estimate the
third-order optical susceptibility, chi((3)) (-omega; omega, -omega, omega)
, of thin films prepared from cadmium sulfide (Cds) colloidal solutions. Th
e formation of CdS films on a substrate, without any change in the particle
size, enhanced the quantum yield of an excitonic band by removing a large
number of surface traps. This film showed a large chi((3)) value near simil
ar to 10(-7) esu around the exciton resonance at room temperature. This was
possibly brought about by an effective surface passivation as well as a hi
gh CdS microcrystallite concentration.