Quadratic nonlinear optical coefficients of organic-inorganic crystal: 2-amino-5-nitropyridinium chloride

The quadratic nonlinear optical efficiency of the 2-amino-5-nitropyridinium dihydrogen chloride crystal is studied. The quadratic coefficients are determined by second-harmonic generation as d11=9 pm/V and d12=8 pm/V. The effective coefficients are obtained as deff=5.1 pm/V for type I and deff=9.7 pm/V for type II. Following the gas-oriented model, the dimensions of the hyperpolarizability tensor bIJK of the 2-amino-5-nitropyridinium are examined. Considering the arrangement of the organic and inorganic entities in the unit cell, the failure of the two-dimensional model can be due to the local electric field induced by the Cl- anions.