title: Nonlinear optical properties of 2,4,5-Trimethoxy-4-nitrochalcone: observation of two-photon-induced excited-state nonlinearities.
abstract: We report experimental investigations of optical nonlinearities and nonlinear dynamics in acetone solution of 2,4,5-Trimethoxy-4- nitrochalcone. By performing Z-scans with femtosecond laser pulses at low excitation intensity, two-photon absorption (2PA) and third-order nonlinear refraction are measured. As laser excitation intensity exceeds a critical value, however, the interplay between third- and fifth-order nonlinearities is observed. It is also confirmed that fifth-order processes mainly originate from 2PA-induced excited-state nonlinearities by conducting femtosecond time-resolved degenerate pump-probe measurements. All the nonlinear parameters are determined unambiguously in the near infrared region of the 2PA cross-section, second-order hyperpolarizability, excited-state absorption cross-section, excited-state refraction cross-section, lifetime of excited states induced by 2PA, and critical population of the excited states in 2,4,5-Trimethoxy-4-nitrochalcone molecule.
authors.affiliation: Jiangsu Key Laboratory on Opto-Electronic Technology and Department of Physics, Nanjing Normal University, Nanjing 210097, China. gubing@njnu.edu.cn
authors.forename: Bing
authors.initials: B
authors.lastname: Gu
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.forename: Xiao-Qin
authors.initials: XQ
authors.lastname: Huang
authors.forename: P S
authors.initials: PS
authors.lastname: Patil
authors.forename: S M
authors.initials: SM
authors.lastname: Dharmaprakash