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Abstract: The nonlinear optical properties of an azo-based dye were investigated using Z-scan technique employing 38ps pulses at 532 and 1064nm, and 6ns laser pulses at 532nm. Large nonlinear absorption and nonlinear refraction were observed at both ps and ns 532nm in the azoic dye. When excited at ps 1064nm, this dye displayed a large two-photon absorption cross-section (σ 2=1810GM). Meanwhile, the optical nonlinearity mechanism was discussed in terms of molecular structure, excitation wavelength, and pulse width. [ABSTRACT FROM AUTHOR]

Abstract: The nonlinear refraction and photoinduced birefringence of chlorophosphonazo I (CPA I ) doped PVA thin films were investigated. The single-beam Z-scan measurement showed that CPA I doped PVA thin film possessed a large value of nonlinear refractive index (n 2=1.82×10−12 cm2/W) under a pulse 532nm excitation, and the mechanism accounting for the process of nonlinear refraction was discussed in term of resonant electronic effect. Moreover, fast and stable molecular reorientation was observed when investigating the photoinduced birefringence of CPA I doped PVA thin film with a CW 532nm laser as pump light and a CW 650nm laser as probe light. [Copyright &y& Elsevier]