Nonlinear optical properties of an azo-based dye irradiated by picosecond and nanosecond laser pulses

• Published in: Physica. B, Condensed matter Vol. 406; no. 3; pp. 488 - 493
• Main Authors: He, Tingchao, Wang, Changshun, Zhang, Chaozhi, Lu, Guoyuan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.02.2011; Elsevier
• Subjects: Condensed matter; Cross sections; Dyes; Exact sciences and technology; Excitation; Fundamental areas of phenomenology (including applications); H-shaped azoic dye; Lasers; Nanocomposites; Nanostructure; Nonlinear refraction; Nonlinearity; Optical materials; Optical properties; Optics; Other nonlinear optical materials; photorefractive and semiconductor materials; Physics; Reverse saturable absorption; Two-photon absorption; Reverse saturable absorption; Two-photon absorption; H-shaped azoic dye; Nonlinear refraction; Level crossing; Radiation effects; Energy levels; Organic dye; Molecular structure; Absorption coefficients; Azo dyes; Z scan; Laser pulse; Optical properties; Two-photon processes; Nonlinear optics
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2010.11.020

The nonlinear optical properties of an azo-based dye were investigated using Z-scan technique employing 38 ps pulses at 532 and 1064 nm, and 6 ns laser pulses at 532 nm. Large nonlinear absorption and nonlinear refraction were observed at both ps and ns 532 nm in the azoic dye. When excited at ps 1064 nm, this dye displayed a large two-photon absorption cross-section ( σ 2=1810 GM). Meanwhile, the optical nonlinearity mechanism was discussed in terms of molecular structure, excitation wavelength, and pulse width. ►In this study we have investigated the nonlinear optical properties of an H-shaped azo-based dye. ►Our experimental results indicate that this kind of dye owns large nonlinear absorption and nonlinear refraction under both ps and ns 532 nm excitation. ►We find this dye has large two-photon absorption cross section (=1810▒GM) at ps 1064▒nm due to its special molecular structure. ►We have discussed the optical nonlinearity mechanism in terms of molecular structure, excitation wavelength and pulse width.