We have measured the absolute values of the second-harmonic generation ͑SHG͒ coefficient ͉d͉ for the zinc-blende II-VI semiconductors ZnTe, ZnSe, and ZnS at room temperature. The investigated spectral region of the fundamental radiation F ranges from 520 to 1321 nm using various pulsed laser sources. In the transparent region of the II-VI semiconductors, the SHG coefficient exceeds the values of birefringent materials as ammonium dihydrogen phosphate ͑ADP͒ and potassium dihydrogen phosphate ͑KDP͒ by one or two orders of magnitudes. Above the E 0 band gap a strong dispersion of ͉d͉ is observed, showing a maximum for a second-harmonic frequency close to the E 1 gap. The experimental results are compared to calculated values using a simple three-band model including spin-orbit splitting. Substantial agreement is found to the experimentally observed dispersion of the second-order nonlinear susceptibility. ͓S0163-1829͑98͒06539-4͔

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Recent progress on compact green laser for projection applications based on frequency doubled semiconductor structures will be presented. Avoiding external acousto-or electro-optical modulation for scanning laser displays, the green laser prototypes can be directly modulated in the 20-40MHz range.

Second harmonic generation is investigated in a ZnSe/ZnS0.22Se0.78 waveguide grown by metal organic vapor phase epitaxy on (001) GaAs substrate. Phase matching is achieved by a first order periodic modulation of the nonlinear susceptibility χ(2) within the waveguide structure. The modulation is generated by a focused ion beam implantation technique, resulting in a well confined damage of the crystalline structure. The observed phase matching wavelengths corresponding to various modulation periods between 1.6 and 1.9 μm agree with those predicted by calculations.