Two-photon assisted excited state absorption in multiferroic YCrO3 nanoparticles

We report a novel functionality for the ferroelectric-antiferromagnet YCrO3 powder of optical limiting upon illumination by nanosecond laser pulses at 532 nm. The optical limiting properties are investigated using the open aperture z-scan technique. The obtained nonlinearity fits to a three-photon like absorption mechanism. It is proposed that this nonlinearity is caused by two-photon absorption, followed by excited state absorption. Two different sized samples were investigated and the nonlinearity is found to be size dependent.