Investigation on Third-Order Optical Nonlinearities of Newly Synthesized Stilbazolium Derivative Crystal by Z-scan Technique

摘要

New stilbazolium derivatives chromophores with donor-π-acceptor structure: 2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium naphthalene-2-sulfonate (DESNS) have been synthesized via Knoevenagel condensations reaction. Luminescence property of the grown crystal indicates that the DESNS is an excellent orange and red light emitting material. The chemical etching studies made on the surface of DESNS and to assess the perfection of the grown crystals, which reveals that formation of layer growth pattern. Both the values of dielectric constant and dielectric loss of the crystal were calculated by varying the frequencies at ambient temperature. The effective third-order nonlinear optical susceptibility χ~(3) of the grown crystal have been investigated by Z-scan technique using He-Ne laser at 632.8nm, which is found to be χ~(3) = 3.509×10~(-4)esu. The negative sign of the nonlinear refractive index n_2 = 5.1242×10~(-12) m~2/W indicates that title material exhibits self-defocusing optical nonlinearity.