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Nonresonant-type third-order nonlinearity of high refractive index PbO-TiO2-TeO2 and Nb2O5-TiO2-TeO2 glass has been evaluated by means of third-harmonic generation. The PbO-containing glass show higher χ(3) than Nb2O5-containing glass, and the largest χ(3) of 3.7×10-12 esu is obtained for 10 mol%PbO-10 mol%TiO2-80 mol%TeO2 and 25 mol%PbO-10 mol%TiO2-65 mol%TeO2 glass.

x-Conjugated poly(aryleneethyny1ene) type polymers fC-C-Ar-C=C-Ar'),, (Ar and/or Ar' = pyridine-2,5-diyl or al kylsubstituted arylene) synthesized by a palladium-catalysed coupling reaction are soluble in organic solvents and processable to make good thin films by casting, have large refractive index increment (AnlAc = 0.29-0.38), and exhibit photoluminescence as well as fairly st-mg third harmonic generation, $3) value of about 10-10 esu.

We prepared nonresonant-type homogeneous glasses containing Bi(2)O(3) by the melting method. The thirdorder optical nonlinear susceptibility chi((3)) was found by third-order harmonic generation measurement to be 9.3 x 10(-12) esu. We attribute the nonlinearity of these glasses to the large molar refraction of glasses containing Bi(2)O(3). These glasses also exhibited an ultrafast response time below 200 fs by a degenerate fourwave mixing method using a femtosecond laser, indicating that the nonlinearity of these glasses originated mainly from pure electronic polarization.

Third-order nonlinear optical properties of As2S3 chalcogenide bulk glass are studied experimentally. Third-harmonic generation (THG) measurement shows the value of the third-order susceptibility χ(3) to be 5.6×10−19 m2/V2 (1.0×10−11 esu) at the funda- mental-light wavelength of 2.1 μm. This value is more than 300 times that for a silica glass. The dependence of the THG χ(3) on the wavelength has been measured, which indicates the χ(3) enhancement effect due to three-photon resonance. Optical Kerr shutter operation is also achieved using the chalcogenide glass. The nonlinear refractive index of n2=6.8×10−18 m2/W is obtained at the gate-light wavelength of 700 nm. This value of n2 agrees with that estimated from the THG measurement. Other nonlinear effects such as two-photon absorption for the gate light are discussed.