The Role of Twisting in Driving Excited-State Symmetry Breaking and Enhanced Two-Photon Absorption in Quadrupolar Cationic Pyridinium Derivatives

2021 ◽  
Author(s):  
Alessio Cesaretti ◽  
Anna Spalletti ◽  
Fausto Elisei ◽  
Paolo FOGGI ◽  
Raimondo Germani ◽  
...  
Keyword(s):  
Excited State ◽  
Symmetry Breaking ◽  
Electron Acceptor ◽  
Electron Donors ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon

Two symmetric quadrupolar cationic push-pull compounds with a central electron-acceptor (N+-methylpyrydinium, A+) and different lateral electron-donors, (N,N-dimethylamino and N,N-diphenylamino, D) in a D-π-A+-π-D arrangement, were investigated together with their dipolar...

Excited-State and Two-Photon Absorption in Salicylidene Molecules: The Role of Zn(II) Planarization

2016 ◽  
Vol 120 (7) ◽  
pp. 4032-4039 ◽  
Author(s):  
Marcelo G. Vivas ◽  
José Carlos Germino ◽  
Cristina A. Barboza ◽  
Pedro A. M. Vazquez ◽  
Leonardo De Boni ◽  
...  
Keyword(s):  
Excited State ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Role Of Zn

Two-photon absorption spectra of a near-infrared 2-azaazulene polymethine dye: solvation and ground-state symmetry breaking

2013 ◽  
Vol 15 (20) ◽  
pp. 7666 ◽  
Author(s):  
Honghua Hu ◽  
Olga V. Przhonska ◽  
Francesca Terenziani ◽  
Anna Painelli ◽  
Dmitry Fishman ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Absorption Spectra ◽  
Ground State ◽  
Near Infrared ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Polymethine Dye

New two-photon absorption benzotriazole–coumarin dyads: the evidence of internal proton transfer in the excited state

2015 ◽  
Vol 56 (1) ◽  
pp. 236-242 ◽  
Author(s):  
Yulong Gong ◽  
Yao Lu ◽  
Zhenqiang Wang ◽  
Shengtao Zhang ◽  
Ziping Luo ◽  
...  
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon

scholarly journals Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

2019 ◽  
Vol 15 ◽  
pp. 2438-2446 ◽  
Author(s):  
Alessandro Iagatti ◽  
Baihao Shao ◽  
Alberto Credi ◽  
Barbara Ventura ◽  
Ivan Aprahamian ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime of the Z-form depends on solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time-resolved luminescence measurements evidence the presence of a main emission component in the 500–520 nm spectral range, attributed to the Z-isomer, and a very short living blue-shifted emission, attributed to the E-isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.

OPTICAL LIMITING STUDIES IN PHOTOREFRACTIVE PURE AND IRON-DOPED Bi12SiO20 CRYSTALS

2000 ◽  
Vol 09 (02) ◽  
pp. 217-225 ◽  
Author(s):  
P. SREERAMANA AITHAL ◽  
P. PREM KIRAN ◽  
D. NARAYANA RAO
Keyword(s):  
Excited State Absorption ◽  
Optical Limiting ◽  
Photon Absorption ◽  
Limiting Behavior ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Iron Incorporation ◽  
Optical Limiter ◽  
Level Model

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.

scholarly journals Impact of the Subunit Arrangement on the Nonlinear Absorption Properties of Organometallic Complexes with Ruthenium(II) σ-Acetylide and Benzothiadiazole as Building Units §

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 67
Author(s):  
Eleonora Garoni ◽  
Alessia Colombo ◽  
Kenji Kamada ◽  
Claudia Dragonetti ◽  
Dominique Roberto
Keyword(s):  
Electron Acceptor ◽  
Cross Sections ◽  
Nonlinear Absorption ◽  
Organometallic Complexes ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Resonance Enhancement

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.

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