Off-axis quasi-phase-matched second-order optical nonlinearity from χ(2) gratings induced by holographic all-optical poling

We present here the quasi-phase-matched second-harmonic (SH) light of holographic all-optical poling measured along the off-axis direction of the wave vector of 4k(omega) - k(2 omega) + Delta k with Delta k = 0, where k(omega) is the wave vector of omega writing beam, k(2 omega) is the wave vector of 2 omega writing beam, and Delta k is the wave-vector mismatch whose vector is parallel to k(omega). As expected, Delta k not equal 0 of the phase-mismatched condition gave rise to a very low SH signal. Furthermore, tensor components of chi((2)) gratings were analyzed, and the contribution of the photoisomeric state of the cis configuration of azobenzene chromophore studied was discussed. (C) 2011 Optical Society of America