Fig. 1. Geometry of the wide, high intensity fundamental beam interacting with a PPLN array near its phase-matching condition for second harmonic generation.

Fig. 2. The first derivative dk_y/dk_x of the dispersion relation obtained by plotting the centroid at the output facet of a fundamental beam injected into the PPLN arrays as a function of the relative phase between the adjacent channels.

Fig. 3 Output from PPLN array as a function of increasing input fundamental energy. Left-hand-side: positive phase-mismatch of 170π. Right-hand-side: negative phase-mismatch of -40π.

Fig. 4. Spatial Fourier transform of the output intensity patterns shown in Fig. 3.. Left-hand-side: positive phase-mismatch of 170π. Right-hand-side: negative phase-mismatch=-40π.

Fig. 5. Low and high power output intensity distribution from the array at high (green) and low (blue) powers. Left-hand-side: positive phase-mismatch of 170π. Right-hand-side: negative phase-mismatch of -40π.

Fig. 6. Calculated evolution of a seeded fundamental beam in the PPLN array as a function of increasing peak input fundamental power in the middle channel. Experimental parameters were assumed. Left-hand-side: positive phase-mismatch of 170π. Right-hand-side: negative phase-mismatch of -40π.

Fig. 7. Distribution across the array of the fundamental beam output power from the PPLN array for incidence of the fundamental beam as a function of the relative input phase between adjacent channels. Positive phase mismatch = 170π on the left; negative phase-mismatch=-40π on the right. The input pulse energy was 0.27μJ corresponding to a peak power of 620W in the middle channel. Regions of high contrast filaments are identified by ellipses.