3RD-ORDER OPTICAL NONLINEARITIES OF CUCL-DOPED GLASSES IN A NEAR RESONANCE REGION

Third-order optical non-linearities of CuCl microcrystallites with siz es of 6.8-11.0 nm in glasses were investigated. Absolute values of thi rd-order non-linear susceptibilities, \chi((3))(-omega(1): omega(1), - omega(1), omega(1))\, were measured in the resonance region by a gener ate four-wave mixing method and \chi((3))(-omega(2): omega(1), -omega( 1), omega(2))\ were measured in the near resonance region by a non-deg enerate four-wave mixing method. \chi((3))(-omega(1): omega(1), -omega (1), omega(1))\ was strongly dependent on the frequency, omega(1), of incident beam, while \chi((3))(-omega(2): omega(1), -omega(1), omega(2 ))\ was less dependent on the frequency, omega(2), of incident beam un der the resonant excitation condition. In the non-degenerate four-wave mixing configuration in which the pumping frequency is resonant with the confined excitons, the figure of merit, \chi((3))\/alpha, was enha nced to more than an order of magnitude compared with that in the dege nerate four-wave mixing configuration in a near resonance region.