DENDRITIC FLUORENE OLIGOMERS FOR NONLINEAR ABSORPTION IN THE VISIBLE RANGE

2005 ◽  
Vol 14 (03) ◽  
pp. 311-318 ◽  
Author(s):  
CYRIL BARSU ◽  
CHANTAL ANDRAUD ◽  
NADIA AMARI ◽  
SYLVIE SPAGNOLI ◽  
PATRICE L. BALDECK
Keyword(s):  
Nonlinear Absorption ◽  
Excited State Absorption ◽  
Photon Absorption ◽  
Visible Range ◽  
Absorption Process ◽  
Time Duration ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
At Resonance

We report here the nonlinear absorption properties of dendritic molecules of oligofluorenes. Measurements were performed in chloroform between 450 and 650 nm for nanosecond time duration pulses. The nonlinear absorption is attributed to a three-photon absorption process involving first a two-photon absorption (TPA) step followed by an excited state absorption (ESA) process. The corresponding three-photon absorption coefficient α3 presents at resonance high values (α3 > 10000 cm 3/ GW 2 for 2G1 the first dendrimer generation bearing a bifluorene at a concentration of 50 g/L). These values are strongly enhanced with respect to those obtained in the same conditions for analog linear oligofluorenes.

Synthesis and characterization of optical properties of soft and hard Er3+-doped (K Na)NbO3 piezophotonic ceramics

2020 ◽  
Vol 557 (1) ◽  
pp. 73-84
Author(s):  
M. C. dos Santos ◽  
J. A. Eiras ◽  
M. H. Lente
Keyword(s):  
Excited State Absorption ◽  
Photon Absorption ◽  
Visible Range ◽  
Secondary Phases ◽  
Absorption Process ◽  
Photoluminescence Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Potential Applications

Real-time tuning of photoluminescence properties are highly desirable for potential applications. Thus, one proposed approach is to tune the photoluminescence emissions by applying an external electric field. However, in order to switch the ferroelectric polarization, high quality bulk ceramics is demanded. In this work, soft and hard Er3+-doped (K,Na)NbO3 piezophotonic ceramics were prepared by the conventional route and their microstructural, structural and up-conversion emission properties were investigated. Dense and free from secondary phases ceramics were successfully produced. The photoluminescence spectra, in the visible range, were characterized as a function of the pumping power. For the soft composition, a remarkable green shift was verified with increasing the laser power. It was supposed that the excited state absorption, involving a three-photon absorption process, was involved in the 4S3/2→4I15/2 transition. For the hard composition, the two-photon absorption process was dominant and the presence of complex defects reduced significantly the 4F9/2→4I15/2 transition.

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.

PICOSECOND-INDUCED NONLINEAR ABSORPTION IN LIQUID CRYSTAL MEDIA

1995 ◽  
Vol 04 (01) ◽  
pp. 245-260 ◽  
Author(s):  
K. J. McEWAN ◽  
R. C. HOLLINS
Keyword(s):  
Experimental Data ◽  
Liquid Crystal ◽  
Excited State ◽  
Nonlinear Absorption ◽  
Excited State Absorption ◽  
Photon Absorption ◽  
Isotropic Phase ◽  
Pump Probe ◽  
Two Photon Absorption ◽  
Two Photon

The contributions to the nonlinear absorption of liquid crystal media in their isotropic phase are measured using a picosecond pump/probe technique at 587 nm. Good agreement between the experimental data and theory is obtained by assuming that two-photon absorption and excited state absorption dominate the nonlinear optical response. The important parameters are extracted from the experimental data and it is shown that the nonlinear absorption depends strongly on the molecular structure. The lifetime of the excited state is measured and found to compare well with the fluorescence lifetime.

Red to Green Upconversion in Er3+-Doped BaTiO3 Nanorods

2008 ◽  
Vol 8 (12) ◽  
pp. 6564-6568 ◽  
Author(s):  
Márcio A. R. C. Alencar ◽  
Glauco S. Maciel ◽  
Cid B. de Araújo ◽  
Amitava Patra
Keyword(s):  
Excited State ◽  
Excitation Spectrum ◽  
Ground State ◽  
Laser Power ◽  
Excited State Absorption ◽  
Photon Absorption ◽  
Absorption Process ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Upconversion Emissions

We investigated the frequency upconversion (UC) process in BaTiO3:Er3+ nanocrystals for excitation wavelengths in the range 638 to 660 nm. Green upconversion emissions at 526 and 547 nm corresponding to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 to transitions of the Er3+ were observed. The excitation spectrum for UC emissions presented three bands, due to ground state and excited state absorption of Er3+ ions. The UC intensity as a function of the laser power was investigated and it was found this a two-photon absorption process.

Two-photon absorption and excited state absorption properties of an organic dye PSPI

2004 ◽  
Vol 241 (1-3) ◽  
pp. 215-219 ◽  
Author(s):  
Guangyong Zhou ◽  
Dong Wang ◽  
Xiaomei Wang ◽  
Zongshu Shao ◽  
Minhua Jiang
Keyword(s):  
Excited State ◽  
Excited State Absorption ◽  
Organic Dye ◽  
Photon Absorption ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon

Theoretical Investigation on the One- and Two-photon Absorption Properties of Porphyrin-thiophene Chromophores

2009 ◽  
Vol 27 (7) ◽  
pp. 1269-1279 ◽  
Author(s):  
Wenchao LI ◽  
Jikang FENG ◽  
Aimin REN ◽  
Xiangbiao ZHANG ◽  
Chiachung SUN
Keyword(s):  
Theoretical Investigation ◽  
Photon Absorption ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
The One

Substituent effects on the aggregation-induced emission and two-photon absorption properties of triphenylamine–dibenzo[a,c]phenazine adducts

2017 ◽  
Vol 1 (7) ◽  
pp. 1396-1405 ◽  
Author(s):  
Ji Yang ◽  
Yuting Gao ◽  
Tao Jiang ◽  
Wen Liu ◽  
Chenchen Liu ◽  
...  
Keyword(s):  
Substituent Effects ◽  
Photon Absorption ◽  
Absorption Properties ◽  
Aggregation Induced Emission ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Combined Features

Non-substituted and alkyl-substituted triphenylamine–dibenzo[a,c]phenazine adducts (Q1–Q3) showed the combined features of ICT plus AEE, while the alkoxy-substituted Q4–Q5 exhibited obvious AIE effects.

Sign in / Sign up

Export Citation Format

Share Document