Theoretical and experimental studies of three-photon-induced excited-state absorption

Abstract

We theoretically and experimentally study excited-state absorption ͑ESA͒ induced by three-photon absorption ͑3PA͒ under the excitation of ultrafast laser pulses. Based on five-level rate-equation theory, we obtain an analytical expression for the effective four-photon absorption coefficient that originates from both singlet-singlet ͑S-S͒ and triplet-triplet ͑T-T͒ ESA. We validate that the T-T ESA could be justifiably neglected in the femtosecond regime. Experimentally, we verify it in acetone solution of 2,4,5-trimethoxychalcone by performing femtosecond Z-scan measurements; at low excitation intensity, only 3PA is determined; and under the excitation of high intensity, however, we observe the concurrence of 3PA and 3PA-induced S-S ESA processes.

3D grafting via three-photon induced photolysis of aromatic azides

“…2b a value of 1.19 × 10 −78 cm 6 s 2 was obtained for the 3PA cross-section of BAC-M. The obtained values are very close to those recently reported for a similar compound by Gu et al [13].…”

Ultrafast Nonlinear Optical and Optical Limiting Properties of Phthalocyanine Thin Films Studied Using Z-Scan

“…The nonlinear absorption in such molecules is indeed complex phenomena involving several excited state mechanisms such as 2PA/3PA induced excited state absorption, pure 2PA/3PA, single photon induced excited state absorption etc. [37][38][39][40][41]. Further detailed wavelength and intensity dependent studies are in progress to elucidate the complete nonlinear absorp-tion behavior in these materials.…”

Intramolecular charge transfer enhanced optical limiting in novel hydrazone derivatives with a D1–D–Ai–π–A structure

“…Many materials have been found to achieve an optical limiting effect based on multi-photon absorption induced excited-state absorption. 9,[17][18][19][20] Among these materials, organic molecules have attracted great interest due to their good thirdorder nonlinear optical (NLO) properties. [21][22][23] In addition, the nonlinear optical responses in these molecules are tunable by structure modifications.…”