scholarly journals More Than 50-Fold Enhanced Nonlinear Optical Response of Porphyrin Molecules in Aqueous Solution Induced by Mixing Base and Organic Solvent

2021 ◽  
Vol 11 (11) ◽  
pp. 4892
Author(s):  
Satoshi Imura ◽  
Takayoshi Kobayashi ◽  
Eiji Tokunaga
Keyword(s):  
Aqueous Solution ◽  
Triplet State ◽  
Laser Irradiation ◽  
State Formation ◽  
Continuous Wave ◽  
Excited State Absorption ◽  
Solvent Mixture ◽  
Saturable Absorption ◽  
Mixture Ratio ◽  
Quenching Effect

The difference absorption spectrum (DAS) of porphyrin molecules (tetraphenyl-porphyhrin sulfonic acid, TPPS) in aqueous solution induced by continuous wave laser irradiation has been reported previously. It was interpreted that the DAS was caused by the formation of TPPS aggregates induced by laser irradiation. However, transient spectra similar in their shape have already been reported and are attributed to the excited-state absorption and saturable absorption (SA) effects due to the triplet state formation in TPPS. In the present study, we investigated the triplet quenching effect by O2 on the DAS of TPPS aqueous solution and revealed that it originated from the triplet state formation. We also found that mixing the appropriate amount of MeOH and NaOH in TPPS aqueous solution increased its absorbance change by more than 50 times. This may be due to the decrease in dissolved oxygen concentration by mixing them. This result suggests the possibility of controlling the performance of NLO materials by adjusting the solvent mixture ratio and base/acid concentration.

Effect of Aggregation on Bacteriochlorin a Triplet-state Formation: A Laser Flash Photolysis Study¶

2002 ◽  
Vol 76 (5) ◽  
pp. 480 ◽  
Author(s):  
Xavier Damoiseau ◽  
Francis Tfibel ◽  
Maryse Hoebeke ◽  
Marie-Pierre Fontaine-Aupart
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Mechanism of microlens formation in quantum dot glasses under continuous-wave laser irradiation

2001 ◽  
Vol 89 (12) ◽  
pp. 8273-8278 ◽  
Author(s):  
Yuri Kaganovskii ◽  
Irena Antonov ◽  
Fredrick Bass ◽  
Michael Rosenbluh ◽  
Audrey Lipovskii
Keyword(s):  
Quantum Dot ◽  
Laser Irradiation ◽  
Continuous Wave ◽  
Continuous Wave Laser ◽  
Wave Laser

Size reduction of gold particles in aqueous solution by pulsed laser irradiation

1998 ◽  
Vol 72 (7) ◽  
pp. 789-791 ◽  
Author(s):  
Hideaki Kurita ◽  
Akinori Takami ◽  
Seiichiro Koda
Keyword(s):  
Aqueous Solution ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Size Reduction ◽  
Gold Particles ◽  
Pulsed Laser Irradiation

Effects of extending the π-conjugation of the acetylide ligand on the photophysics and reverse saturable absorption of Pt(ii) bipyridine bisacetylide complexes

2016 ◽  
Vol 18 (41) ◽  
pp. 28674-28687 ◽  
Author(s):  
Taotao Lu ◽  
Chengzhe Wang ◽  
Levi Lystrom ◽  
Chengkui Pei ◽  
Svetlana Kilina ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Substituent Effect ◽  
Excited State Absorption ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Triplet Excited State ◽  
Near Ir ◽  
Terminal Substituent ◽  
Acetylide Ligand

Extending the acetylide ligand π-conjugation diminishes the terminal substituent effect on the lowest excited states, but expands the triplet excited-state absorption to the near-IR region.

scholarly journals Generation of Biocompatible Titanium Alloy Surfaces Including Calcium and Phosphorus Elements by Laser-Induced Mist Spraying Wet Treatment

2020 ◽  
Vol 14 (4) ◽  
pp. 575-581
Author(s):  
Atsushi Ezura ◽  
Kazutoshi Katahira ◽  
Jun Komotori ◽  
◽  
◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Laser Irradiation ◽  
Hard Tissue ◽  
Complicated Shape ◽  
Osteoblast Cells ◽  
Cell Compatibility ◽  
P Elements ◽  
Test Pieces ◽  
Modified Surface ◽  
Contact Part

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as compared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

scholarly journals Threshold of permanent cornea thermal damage due to incidental continuous wave CO2 laser irradiation

2010 ◽  
Vol 14 (2) ◽  
pp. 459-467 ◽  
Author(s):  
Mayada Tahir
Keyword(s):  
Laser Irradiation ◽  
Co2 Laser ◽  
Thermal Damage ◽  
Continuous Wave ◽  
Anterior Part ◽  
Outer Part ◽  
Human Cornea ◽  
Thermal Dose ◽  
Element Analysis ◽  
Reflex Blink

Cornea thermal damage due to incidental continuous wave CO2 laser irradiation is studied numerically based on bio-heat equation. The interaction of laser with tissue leads to a rapid temperature increased in target and the nearby tissue. As the temperature of the eye surface reaches 44?C, a sensation of pain will cause aversion response of the reflex blink and/or shifting away from the source of pain. The aim of the work is to predict numerically the threshold limit of incidental laser power that causes damage to the anterior part of the cornea, which can be healed within 2-5 days as long as damage is not exceeding the outer part of the eye (epithelium). A finite element analysis is used to predict temperature distribution through the cornea where the necroses region can be obtained using thermal dose equation. The thermal dose that required for damaging the cornea is predicted from previously published experimental data on rhesus monkeys and used later as a limit for shrinkage to human cornea. The result of this work is compared by international standard of safety and a good nearby result is obtained which verified the result of this work.

scholarly journals Fused ring effect on optical nonlinearity and structure property relationship of anthracenyl chalcone based push-pull chromophores

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257808
Author(s):  
Dian Alwani Zainuri ◽  
Mundzir Abdullah ◽  
Muhamad Fikri Zaini ◽  
Hazri Bakhtiar ◽  
Suhana Arshad ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Electrostatic Potential ◽  
Nonlinear Refractive Index ◽  
Optical Switching ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Excited State Absorption ◽  
Nonlinear Optical Properties ◽  
Closed Aperture

The Ultraviolet-visible (UV-Vis) spectra indicate that anthracenyl chalcones (ACs) have high maximum wavelengths and good transparency windows for optical applications and are suitable for optoelectronic applications owing to their HOMO–LUMO energy gaps (2.93 and 2.76 eV). Different donor substituents on the AC affect their dipole moments and nonlinear optical (NLO) responses. The positive, negative, and neutral electrostatic potential regions of the molecules were identified using molecular electrostatic potential (MEP). The stability of the molecule on account of hyperconjugative interactions and accompanying charge delocalization was analyzed using natural bond orbital (NBO) analysis. Open and closed aperture Z-scans were performed using a continuous-wave frequency-doubled diode-pumped solid-state (DPSS) laser to measure the nonlinear absorption and nonlinear refractive index coefficients, respectively. The valley-to-peak profile of AC indicated a negative nonlinear refractive index coefficient. The obtained single crystals possess reverse saturation absorption due to excited-state absorption. The structural and nonlinear optical properties of the molecules have been discussed, along with the role of anthracene substitution for enhancing the nonlinear optical properties. The calculated third-order susceptibility value was 1.10 x10-4 esu at an intensity of 4.1 kW/cm2, higher than the reported values for related chalcone derivatives. The NLO response for both ACs offers excellent potential in optical switching and limiting applications.

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