Third-order nonlinear optical studies of newly synthesized polyoxadiazoles containing 3,4-dialkoxythiophenes

• Published in: Chemical physics Vol. 331; no. 1; pp. 125 - 130
• Main Authors: Udayakumar, D., John Kiran, A., Adhikari, A. Vasudeva, Chandrasekharan, K., Umesh, G., Shashikala, H.D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 11-12-2006
• Subjects: Conjugated polymers; DFWM; Nonlinear optics; Optical limiting; Z-scan; Optical limiting; Conjugated polymers; Z-scan; Nonlinear optics; DFWM
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2006.10.001

The third-order nonlinear optical properties of newly synthesized soluble polyoxadiazoles containing 3,4-dialkoxythiophenes were investigated by using Z-scan and degenerate four-wave mixing (DFWM) techniques. The measurements were performed at 532
nm with 7
ns pulses from a Nd:YAG laser. We found a good agreement between the values of
χ
(3) determined from both the experiments. Z-scan results indicate a negative nonlinear refractive index,
n
2, whose magnitude is of the order of 10
−10
esu for all the copolymers. The variation of nonlinear response among the copolymers clearly indicates the dependence of
χ
(3) on donor and acceptor type of units present in these copolymers. The copolymers exhibit strong reverse saturable absorption and good optical limiting properties at 532
nm.