Strong Two-Photon Absorption in Push−Pull Phthalocyanines:  Role of Resonance Enhancement and Permanent Dipole Moment Change upon Excitation

2008 ◽  
Vol 112 (3) ◽  
pp. 848-859 ◽  
Author(s):  
Mikhail Drobizhev ◽  
Nikolay S. Makarov ◽  
Aleksander Rebane ◽  
Gema de la Torre ◽  
Tomás Torres
2004 ◽  
Vol 82 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Xin Zhou ◽  
Ai-Min Ren ◽  
Ji-Kang Feng ◽  
Xiao-Juan Liu

The one-photon absorption (OPA) properties of tetrabenzoporphyrins (TBPs) and phthalocyanines (Pcs) were studied using the semiempirical ZINDO method and time-dependent density functional theory (TDDFT), respectively. The compared results confirmed that the semiempirical ZINDO method was reasonably reliable when calculating the OPA of tetrabenzoporphyrins and phthalocyanines. On the basis of the OPA properties obtained from the ZINDO method, two-photon absorption (TPA) properties of two series of molecules were investigated, using ZINDO and sum-over-states (SOS) methods. The results showed that the TPA cross-sections of all molecules were in the range of 220.6 × 10–50 – 345.9 × 10–50 cm4·s·photon–1, which were in the same order of magnitude as the values reported in the literature. The relatively larger δ(ω) value for Pcs with respect to that for corresponding TBPs originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment between S0 and S1 and the transition dipole moment between S1 and S5.Key words: two-photon absorption, ZINDO, sum-over-states, tetrabenzoporphyrin, phthalocyanines.


2000 ◽  
Vol 09 (02) ◽  
pp. 217-225 ◽  
Author(s):  
P. SREERAMANA AITHAL ◽  
P. PREM KIRAN ◽  
D. NARAYANA RAO

Optical limiting characteristics of pure and 150 ppm Fe-doped Bi 12 SiO 20 (BSO:Fe) crystals are studied at high intensity nanosecond pulse regime. When the input light is at 532 nm and at 595 nm with 6 ns pulse duration, a good optical limiting behavior is observed due to simultaneous effect of trap assisted excited state absorption and two photon absorption. The precise role of the internal defects due to impurity centers present in the crystal lattice is explained on the basis of a four level model. This study reveal that the increased nonlinear absorption due to iron incorporation in BSO makes it an excellent passive optical limiter.


Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 67
Author(s):  
Eleonora Garoni ◽  
Alessia Colombo ◽  
Kenji Kamada ◽  
Claudia Dragonetti ◽  
Dominique Roberto

In this paper, the nonlinear absorption properties of two complexes consisting of Ru(C≡CPh)(C≡C)(dppe)2 (dppe = Ph2PCH2CH2PPh2) as electron donor (D) and 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole as electron acceptor (A) units in two different arrangement, i.e., A–D–A and D–A–D, are presented. They were measured in solution by the femtosecond open-aperture Z-scan method. The complexes show moderate two-photon absorption cross-sections σ(2) of several hundred to one thousand GM (here 1 GM = 10−50 cm4 s molecule−1 photon−1). Although they are formed by the same building units, it was found that the two-photon absorption values of the D–A–D arrangement are six times higher than that of the A–D–A one. This difference can be explained by the number of metal cores (one or two ruthenium centers), the geometrical configurations of the complexes (more or less planar), and the resonance enhancement by lowering the intermediate state.


2010 ◽  
Author(s):  
Gero Nootz ◽  
Lazaro A. Padilha ◽  
Scott Webster ◽  
David J. Hagan ◽  
Eric W. Van Stryland ◽  
...  

2007 ◽  
Vol 111 (50) ◽  
pp. 14051-14054 ◽  
Author(s):  
M. Drobizhev ◽  
N. S. Makarov ◽  
T. Hughes ◽  
A. Rebane

2004 ◽  
Vol 82 (7) ◽  
pp. 1172-1178 ◽  
Author(s):  
Xin Zhou ◽  
Ai-Min Ren ◽  
Ji-Kang Feng ◽  
Xiao-Juan Liu

The one-photon and two-photon absorption properties of donor–acceptor substituted dehydrobenzo[18]annulenes were determined by using density functional theory and ZINDO methods. The macrocycle containing C2v symmetry exhibited the largest TPA cross-section value of 3376 × 10–50 cm4 s/photon. The calculated results indicate that the TPA response in the whole molecule comes from the contribution of that in the every side in the trigon. It is notable that the magnitudes of the transition dipole moment from the virtual intermediate state to the TPA final state and the dipole moment difference between the ground state and the virtual intermediate state play important roles in increasing the TPA cross-section value. This series of molecules can circumvent the trade-off between efficiency and transparency, and they provide a promising direction for the further development of novel two-dimensional molecules with such properties.Key words: two-photon absorption, ZINDO, sum-over-states, dehydrobenzo[18] annulenes, transparency.


2009 ◽  
Vol 81 (1) ◽  
pp. 63-68 ◽  
Author(s):  
M. Fakis ◽  
I. Fitilis ◽  
S. Stefanatos ◽  
P. Vellis ◽  
J. Mikroyannidis ◽  
...  

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