Descrição
Chalcones are a family of organic compounds that exhibit good nonlinear optical properties. (1) Additionally, they have a relatively simple synthesis and various pharmacological properties, making them promising subjects of study, with potential applications in areas such as bio-photonics. (2) In this work we study the dynamics of excited states and the effect of substituents (electron donors and acceptors) on the two-photon absorption (2PA) cross-section of bromo-chalcone derivatives using the z-scan technique. (3) Nonlinear optical experiments are performed using 200-fs pulses from a YGW laser system, which, when coupled with an optical parametric amplifier, allows for tuning the excitation wavelength from the UV to the near-infrared. Therefore, the 2PA cross-section spectrum is obtained, enabling to correlate the nonlinear optical response with the molecular structure. Initially we have selected a few chalcone compounds, which were diluted in DMSO, and their linear absorption and fluorescence spectra have been measured. It was observed that the samples exhibited two UV absorption bands, except for the one with the amino group (-NH2), which showed a significant shift of the first band (now centered at 432 nm). Such a molecule was also the only one that exhibited fluorescence, centered at 558 nm. Yet, from the open aperture (absorptive) z-scan measurements with this sample, it was observed that the transitions allowed by one photon were also allowed by two photons, which is a characteristic of a non-centrosymmetric molecule. Further studies are being performed with the other chalcone compounds to correlate the nonlinear spectrum and specific molecular features.
Referências
1 ARSHAD, M. N. et al. Synthesis, crystal structures, spectroscopic and nonlinear optical properties of chalcone derivatives: a combined experimental and theoretical study. Journal of Molecular Structure, v. 1141, p. 143-156, Aug. 2017.
2 SALEHI, B. et al. Pharmacological properties of chalcones: a review of preclinical including molecular mechanisms and clinical evidence. Frontiers in Pharmacology, v. 11, p. 592654-1-592654-21, Jan. 2021.
3 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.
| Certifico que os nomes citados como autor e coautor estão cientes de suas nomeações. | Sim |
|---|---|
| Palavras-chave | Two-photon absorption. Bromo-chalcone derivatives. Z-scan. |
| Orientador e coorientador | Cleber Renato Mendonça |
| Subárea 1 | Fotônica |
| Subárea 2 (opcional) | Óptica |
| Agência de Fomento | CAPES |
| Número de Processo | 88887.803863/2023-00 |
| Modalidade | MESTRADO |
| Concessão de Direitos Autorais | Sim |
