Third-order optical non-linearities of CuCl-doped glasses in a near resonance region

Third-order optical non-linearities of CuCl microcrystallites with sizes of 6.8-11.0 nm in glasses were investigated. Absolute values of third-order non-linear susceptibilities, \chi((3))(-omega(1): omega(1), -omega(1), omega(1))\, were measured in the resonance region by a generate 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-degenerate 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 under 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 enhanced to more than an order of magnitude compared with that in the degenerate four-wave mixing configuration in a near resonance region.