13ª Semana Integrada do Instituto de Física de São Carlos

Effect of dimethylamine group on the nonlinear optical properties and fluorescence enhancement of acetamide-chalcone derivatives

21 de ago. de 2023 10:30

1h 30m

Salão de Eventos USP

Básica 10h30 - 12h00

Descrição

Here it was studied the influence of eight peripherical groups on the photophysical and nonlinear optical properties of acetamide-chalcone derivatives. Nonlinear optical measurements such the tunable Z-Scan technique and fluorescence through multiphoton excitation (MPE) were performed in femtosecond regime. (1-2) Results revealed that the incorporation of the dimethylamine group leaded to large fluorescence quantum yield (71% in DMSO solution) that can be triggered by MPE, which is important for biological applications. Furthermore, dimethylamine also red-shifts the lower energy band by about 90 nm, increasing its two-photon absorption cross-section by more than 100% regarding the other studied molecules of this work. Besides, all compounds displayed two-electronic states observed through one and two-photon absorption spectroscopy and confirmed by Quantum Chemistry Calculations (QCCs). The Sum Over States approach was used to model the two-photon absorption cross section spectrum off all compounds which showed a strong dependence between the coupling of the ground state with the first excited state. (3)

Referências

1 SHEIK-BAHAE, M et al. Sensitive measurement of optical nonlinearities using a single beam. IEEE Journal of Quantum Electronics, v. 26, n. 4, p. 760-769, Apr. 1990. DOI: https://doi.org/10.1109/3.53394.

2 SHEIK-BAHAE, M.; SAID, A. A.; VAN STRYLAND, E. W. High-sensitivity, single-beam n2 measurements. Optics Letters, v. 14, n. 17, p. 955-957, 1989. DOI: https://doi.org/10.1364/OL.14.000955.

3 MEATH, W. J.; POWER, E. A. On the importance of permanent moments in multiphoton absorption using perturbation theory, Journal of Physics B, v. 17, n. 5, p. 763-781, 1984. DOI: https://doi.org/10.1088/0022-3700/17/5/017.