Nonlinear Optical and Electrooptical Effects in 2-Methyl-4-Nitro-N-Methylaniline (MNMA) Crystals

Single crystals of 2-methyl-4-nitro-N-methylaniline (MNMA) have been grown from the melt. The crystal structure was determined (orthorhombic, Pna2 (2 mm), Z = 4, a = 17.788(6) Å, b = 11.893(4) Å, c = 3.907(2) Å). The refractive indexes na and nc were measured between 500 and 700 nm [na(633 nm) = 2.148(10), nc(633 nm) = 1.520(3)]. The nonlinear optical susceptibilities d31 = 13 pm/V, d33 = 2.6 pm/V, d15 = 12 pm/V and the electrooptic coefficients r31 = 8 pm/V and r33 = 7.5 pm/V were determined. Most optical properties can be explained in terms of molecular orientation and polarizability. © 1988 IEEE