Media polarity and concentration roles on the third order nonlinear behaviors of thiazine dyes

• Published in: Optics and laser technology Vol. 100; pp. 216 - 224
• Main Authors: Khadem Sadigh, M., Zakerhamidi, M.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2018; Elsevier BV
• Subjects: Absorption; Control methods; Dyes; Excitation; Experiments; Media polarity; Molecules; Nonlinear control; Optical materials; Optics; Performance enhancement; Photonics; Polarity; Reverse saturable absorption; Saturation; Solvents; Thiazine dye; Wavelengths; Thiazine dye; Reverse saturable absorption; Media polarity; Saturation
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2017.10.007

•Nonlinearity depends on molecular structure, linear feature, media and concentration.•Thiazine dyes indicate high nonlinearity in diluted polar aprotic solutions.•Saturable and reverse saturable absorptions are controllable by excitation beam. Nonlinear optical materials play important roles in optics and photonics. In order to improve the performance of these materials, in this paper, we tried to find effective methods for controlling the nonlinear responses of thiazine dyes. Our experimental results indicate that molecular linear properties, media polarity, concentration and excitation beam properties with different contributions play significant roles on the saturable and reverse saturable absorption characteristics of thiazine dyes. In real, competition between these effective parameters leads to appearance of various third order nonlinear responses. Although by excitation wavelengths near the absorption peaks and at high powers, dye molecules tend to indicate reverse saturable absorption characteristics in polar protic solvents by increasing the concentration, saturable absorption characteristics were observed in polar aprotic solvents. Furthermore, the samples displayed the same behaviors in different solvent media at low powers and for excitation wavelengths far from absorption peaks. Therefore, by controlling the nonlinear responses of thiazine dyes, these materials can indicate both saturable and reverse saturable absorption characteristics that increase their applications in optics and photonics devices.