Third-order nonlinear optical properties of trans-dihydroxy-1,6,11,16-tetra(tert.butyl)porphyrazine germanium thin films

Third-order nonlinear optical susceptibilities χ(3) of trans-dihydroxy-1,6,11,16-tetra-(tert.butyl) porphyrazine germanium [t-Bu4PazGe(OH)2] thin films measured by the third-harmonic generation technique are reported for the first time. The χ(3)(−3ω;ω,ω,ω) value as high as 1.3×10−11 esu was observed from a dominant three-photon resonance. The χ(3) values of porphyrazine germanium derivative are analogous to metallophthalocyanines and these results imply that axial substitution is beneficial for enhancing third-order optical nonlinearity.