Spectroscopy and Nonlinear Absorption of α, ω-dithienyi Polyenes

1997 ◽  
Vol 479 ◽  
Author(s):  
L. V. Natarajan ◽  
Laura A. Sowards ◽  
C. W. Spangler ◽  
N. Tang ◽  
P. A. Fleitz ◽  
...  

AbstractThe photophysics and nonlinear absorption behaviour of a series of α, ω-dithienyl polyenes were studied in chloroform and n-octane solutions. Steady state fluorescence, fluorescence lifetime and quantum yield measurements were made. The fluorescence quantum yields were significantly lower than those of the corresponding ax,o-diphenyl polyenes. Among the dithienyl polyenes, 3,3′-substituted polyenes exhibited stronger fluorescence than those of the 2,2′-substituted. Nonlinear optical absorption experiments showed evidence of two photon absorption.

2020 ◽  
Vol 49 (23) ◽  
pp. 7737-7746
Author(s):  
Mukundam Vanga ◽  
Shreenibasa Sa ◽  
Anupa Kumari ◽  
Anna Chandrasekar Murali ◽  
Prakash Nayak ◽  
...  

B ← N coordinated phenanthroimidazole dimers exhibit excellent fluorescence quantum yields in solution and conjugation length dependant two-photon-absorption properties.


2003 ◽  
Vol 12 (01) ◽  
pp. 81-89 ◽  
Author(s):  
SHENG-LI GUO ◽  
HUI-TIAN WANG ◽  
N. B. MING ◽  
JUN-YONG ZHANG ◽  
ZHI-JIAN GUO

We describe a modified Z-scan technique for the case when nonlinear refraction is accompanied by nonlinear absorption to separately evaluate the nonlinear refraction and the nonlinear absorption by performing straightforward measurements with the aperture removed. We divide the closed aperture (S < 1) normalized Z-scan by a scan with an open aperture (S = 1). With nanosecond scale at a 532 nm wavelength, we first measured the nonlinear optical absorption and refraction coefficients of a solution of Ni(Ac)2[N-(8-quinolyl) pyridine-2-carboxamide] · 4H2O by using the modified Z-scan technique. The nonlinear absorption originates from the near resonant two-photon absorption while the mechanism of the nonlinear refraction is the near resonant two-photon absorption transition enhancement. The linear increasing dependences of the optical nonlinearities on the incident irradiance arise from the population redistribution due to the near resonant two-photon absorption.


1999 ◽  
Vol 561 ◽  
Author(s):  
Thomas M. Cooper ◽  
Paul A. Fleitz ◽  
Laura A. Sowards ◽  
Lalgudi V. Natarajan ◽  
Sean Kirkpatricky ◽  
...  

ABSTRACTTo understand the properties of light-sensitive compounds used in optical limiters having photoinduced charge transfer mechanisms, we have investigated the photophysics of a series of di(2-thienyl-3,3'-butyl)polyenes. Spectroscopic measurements, including UV/Vis, fluorescence, fluorescence lifetimes, fluorescence quantum yields, triplet state lifetime, solvent effects and two-photon absorption coefficient were obtained as a function of the number of double bonds(n = 1-5). Trends in the data reflected the ordering, energy gap between and mixing of 1Bu* and 1Ag* excited state configurations.


2011 ◽  
Vol 25 (12n13) ◽  
pp. 1003-1011 ◽  
Author(s):  
TRAN CONG PHONG ◽  
HUYNH VINH PHUC

Applying the theory of nonlinear optical conductivity for an electron—phonon system, we propose a new method to obtain the line-widths of nonlinear optical conductivity in rectangular quantum wires (RQW). General analytical expressions of the nonlinear absorption power (NLAP) are obtained in the presence of an intense external field. A two-photon absorption process is taken into the result. The dependence of NLAP on the photon energy and the wire's size are numerically calculated and graphically plotted for a specific RQW. From graphs of the NLAP, we obtain line-widths as profiles of curves. The dependence of the line-widths on the temperature and parameters of a RQW are reasonable in comparison with some available theoretical and experimental results.


2015 ◽  
Vol 3 (15) ◽  
pp. 3730-3744 ◽  
Author(s):  
C. Lavanya Devi ◽  
K. Yesudas ◽  
Nikolay S. Makarov ◽  
V. Jayathirtha Rao ◽  
K. Bhanuprakash ◽  
...  

A series of fluorenylethynylpyrene derivatives with large two-photon absorption cross-sections (≈250–2500 GM) and good fluorescence quantum yields (Φfl = 0.55–0.98) and with high two-photon brightness were synthesized.


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