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    Item type:Publication,
    Third-harmonic generation enhancement in polymer-dispersed liquid crystal grating
    (2014-01-01)
    Wicharn, S.
    ;
    Buranasiri, P.
    In this paper, the enhancement of third-harmonic generation in one-dimensional periodic grating structure with lowindex contrast, which is produced by holographic illuminated liquid crystal droplets and called polymer-dispersed liquid crystal grating, with near-infrared pumping has been demonstrated. The observed enhancement process is theoretically explained and modeled with a multi-scale perturbation analysis and split-step Fourier transform technique, respectively. We show that the third-harmonic generation has been enhanced by setting the fundamental frequency wavelength to the long-wavelength band-edge of the first photonic band-gap of this periodic structure and satisfying band-edge phasematched condition. The numerical results show that a dramatic enhancement of the third-harmonic field is observed near the long-wavelength band-edge of the second photonic band-gap. Furthermore, the conversion efficiency of thirdharmonic field of forward-propagating direction is more than of backward-propagating direction by a factor of 600.
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    Item type:Publication,
    Efficient third-harmonic generation in one-dimensional photonic crystals
    (2013-09-18)
    Wicharn, S.
    ;
    Buranasiri, P.
    ;
    Ruttanapun, C.
    ;
    Jindajitawat, P.
    In this paper, we have solved nonlinear coupled-mode equations valid for light propagation in a one-dimensional photonic crystal by using numerical expression. Moreover, the medium in this problem has been considered as a nonlinear x <sup>(3)</sup> material. The numerical results have been used to calculate the conversion efficiency in nondepleted-pump limit. The results have been shown us that the maximum conversion efficiency of third-harmonic generation could be occurred when the fundamental field has been tuned near the lower band-edge of photonic band-gap that band-edge phase matched condition has been satisfied. © 2013 SPIE.