Nonlinear optical absorption of [(C{sub}2H{sub}5){sub}4N]{sub}2Cu(dmit){sub}2 irradiated by picosecond and nanosecond laser pulses

摘要

Nonlinear optical absorption of [(C{sub}2H{sub}5){sub}4N]{sub}2Cu(dmit){sub}2 (dmit{sup}(2-)=4,5-dithiolate-1,3-dithiole-2-thione), abbreviated as EtCu, dissolved in acetone has been investigated by open-aperture Z-scan technique with picosecond and nanosecond laser pulses in the near infrared region. Under irradiation with 40 ps laser pulses at 1064 nm, two-photon absorption is observed and the two-photon absorption coefficient β{sub}(TPA) is (5.8±0.3)×10{sup}(-13) m/W. While excited by 15 ns laser pulses at 1053 nm, the sample presents a strong reverse saturable absorption and its nonlinear absorption coefficient β{sub}(RSA) is as high as (1.7 ± 0.1) × 10{sup}(-10) m/W. The mechanism responsible for the difference between the results is analyzed. All the results suggest that this material may be a promising candidate for the application to optical limiting in the near infrared waveband.