Herein, results from the investigation of ultrafast photophysical and third-order nonlinear optical properties of newly synthesized Zn phthalocyanine, namely [Zinc (II) 2,10,16,24tetrakis(2,6-dichloropyridin-3-yl) phthalocyanine, PyCl2PC] molecule are presented. The photophysical properties were studied using femtosecond transient absorption spectroscopy while the NLO properties were measured using the single beam Z-scan and degenerate four-wave mixing (DFWM) techniques. The transient absorption spectra were obtained at 400 nm photoexcitation and a white light continuum probed the corresponding dynamics from (440-780 nm) in the solution phase. The obtained transient absorption spectra were globally fitted using a kinetic model which yielded the different photophysical constants after photoexcitation such as (i) internal conversion from higher electronic excited state (Sn) to lower electronic state (S1) happening in 1 ps (ii) Vibrational relaxation (6.25 ps) occurring within the S1 states (III) Intersystem crossing (1.78 ns) (IV) relaxation from the triplet states to ground state (0.11 μs). Nonlinear absorption properties were measured at 800 nm wavelength utilizing ~70 fs, 1 kHz laser pulses in the solution phase. A large two-photon absorption coefficient (β) of ~8×10-13 cm/W was obtained and the corresponding cross-section was estimated to be 659 GM. Time-resolved degenerate four-wave-mixing measurements revealed a large magnitude and an ultrafast response of χ(3).
We have investigated the ultrafast third-order nonlinear optical (NLO) properties of a novel chalcone derivative, 3-(4- methoxyphenyl)-1-(4-nitrophenyl)prop-2-en-1-one (abbreviated as MNC) by Z-scan and degenerate four-wave mixing (DFWM) techniques using femtosecond Ti:Sapphire laser system (~70fs, 1 kHz, 800 nm). The molecular structure of the synthesized chalcone by Claisen-Schmidt condensation reaction was confirmed by FT-IR and 1H NMR spectroscopic techniques. The thermal stability was studied by thermogravimetric/ differential thermal analysis (TG/DTA) technique and melting point was found to be 177 °C. The linear absorption spectra suggest that the MNC chalcone is optically transparent in the Vis-NIR region. The open aperture Z-scan demonstrated two-photon absorption, evident from the reverse saturable absorption type mechanism, while the closed aperture Z-scan demonstrated a positive nonlinear refraction due to self-focusing effect. Further, the chalcone exhibited optical limiting (OL) and optical switching properties. The onset optical limiting threshold fluence was measured at 9.15 mJ/cm2 and the figures of merit for all-optical-switching were satisfied. From DFWM data we measured the magnitude of NLO coefficients, nonlinear response time and dephasing time. The third-order NLO susceptibility and molecular hyperpolarizability were calculated to be 1.39×10-14 esu and 6.89×10-34 esu, respectively, using Z-scan and 6.53×10-14 esu and 32.7×10-34 esu, respectively, using DFWM techniques. From both these techniques the magnitude of NLO coefficients were found to be in good agreement. The time-resolved DFWM studies revealed that the nonlinear response time of MNC was very short (~112 fs). These results indicate that the MNC chalcone is a potential material for optical limiting and all-optical-switching applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.