Optical limiting and nonlinear optical studies of ferrocenyl substituted calixarenes

Optical limiting behavior of three ferrocenyl substituted calixarenes (FSCs) where ferrocenyl group is attached via ethynyl(a), meta-(b) and para-(c) ethynyl phenyl spacers studied with nanosecond pulses at 532 nm is in the order c > a > b. While, with femtosecond laser pulses at 800 nm strength of nonlinearity is in the order c > b > a. Largest nonlinear refraction (n2 = 9.5 × 10−16 cm2/W) is estimated for the FSC c. Nonlinear absorption in these FSCs is attributed to three-photon absorption. Optical limiting behavior with nanosecond laser pulses is mainly due to thermal nonlinearity and reverse saturable absorption, whereas, with femtosecond laser pulses mainly intrinsic electronic nonlinearity contributes.