Third order nonlinear optical properties and optical limiting behavior of alkali metal complexes of p-nitrophenol

• Metal complexes of p-nitrophenolate (M=Li, Na and K) have been synthesized.
• The third order nonlinear parameters of the samples are determined using Z-scan method.
• Optical limiting properties have been investigated.

Optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol is studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532 nm, 50 mW). The predominant mechanism of observed nonlinearity is thermal in origin. The nonlinear refractive index and the nonlinear absorption coefficient of the samples were found to be in the order of 10−8 cm2/W and 10−3 cm/W respectively. Magnitude of third-order optical parameters varies according to the choice of alkali metal chosen for metal complex formation of p-nitrophenolate. The third-order nonlinear susceptibility was found to be in the order of 10−6 esu. The observed saturable absorption and the self-defocusing effect were used to demonstrate the optical limiting action at 532 nm by using the same cw laser beam.