Effects of Red and Green Laser Irradiations on the Optical Properties of an Azo-Containing Bent-Core Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 588-592
Author(s):  
Yuan Ming Huang ◽  
Fu Fang Zhou ◽  
Bao Gai Zhai
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Optical Absorption ◽  
Laser Irradiation ◽  
Ethyl Alcohol ◽  
Irradiation Time ◽  
Green Light ◽  
Green Laser ◽  
Time Dependent ◽  
532 Nm

With the ultraviolet-visible spectrophotometry, we have investigated the effects of red laser (633 nm) and green laser (532 nm) irradiations on the optical absorption of the ethyl alcohol solutions of an azo-containing bent-core liquid crystal. As the irradiation duration increases, the optical absorptions at about 360 nm of the bent-core compound exhibit concentration dependent and irradiation-time dependent features. The absorptions of dilute solutions (~2.2 mg/litter) are not sensitive to the laser irradiation duration whereas the absorptions of higher concentrations (~10 mg/litter) decrease as the laser irradiation continues. Our results have demonstrated that laser irradiation induced thermolysis is responsible for the dissociation of the azo-linkages in azo-containing bent-core compound. The mechanisms on the red and green light irradiations are discussed.

scholarly journals High-Efficiency Intracavity Continuous-Wave Green-Light Generation by Quasiphase Matching in a Bulk Periodically Poled MgO:LiNbO3 Crystal

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Shaowei Chu ◽  
Ying Zhang ◽  
Bin Wang ◽  
Yong Bi
Keyword(s):  
High Efficiency ◽  
Continuous Wave ◽  
Green Light ◽  
Frequency Doubling ◽  
Green Laser ◽  
Periodically Poled ◽  
Output Stability ◽  
532 Nm ◽  
Better Than ◽  
Quasiphase Matching

908 mW of green light at 532 nm were generated by intracavity quasiphase matching in a bulk periodically poled MgO:LiNbO3 (PPMgLN) crystal. A maximum optical-to-optical conversion efficiency of 33.5% was obtained from a 0.5 mm thick, 10 mm long, and 5 mol% MgO:LiNbO3 crystal with an end-pump power of 2.7 W at 808 nm. The temperature bandwidth between the intracavity and single-pass frequency doubling was found to be different for the PPMgLN. Reliability and stability of the green laser were evaluated. It was found that for continuous operation of 100 hours, the output stability was better than 97.5% and no optical damage was observed.

scholarly journals Laser-Induced Modification of Hydrogenated Detonation Nanodiamonds in Ethanol

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2251
Author(s):  
Irena Bydzovska ◽  
Ekaterina Shagieva ◽  
Ivan Gordeev ◽  
Oleksandr Romanyuk ◽  
Zuzana Nemeckova ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Laser Irradiation ◽  
Structural Changes ◽  
Irradiation Time ◽  
Detonation Nanodiamonds ◽  
High Temperature Annealing ◽  
Inert Environment ◽  
Transmission Electron ◽  
Gradual Loss ◽  
532 Nm

Apart from the frequently used high-temperature annealing of detonation nanodiamonds (DNDs) in an inert environment, laser irradiation of DNDs in a liquid can be effectively used for onion-like carbon (OLC) formation. Here, we used fully de-aggregated hydrogenated DNDs (H-DNDs) dispersed in ethanol, which were irradiated for up to 60 min using a 532 nm NdYAG laser with an energy of 150 mJ in a pulse (5 J/cm2) at a pulse duration of 10 ns and a repetition rate of 10 Hz. We investigated the DND surface chemistry, zeta potential, and structure as a function of laser irradiation time. Infrared spectroscopy revealed a monotonical decrease in the C–Hx band intensities and an increase of the C–O and C=O features. Transmission electron microscopy (TEM) revealed the formation of OLC, as well as a gradual loss of nanoparticle character, with increasing irradiation time. Surprisingly, for samples irradiated up to 40 min, the typical and unchanged DND Raman spectrum was recovered after their annealing in air at 450 °C for 300 min. This finding indicates the inhomogeneous sp3 to sp2 carbon transformation during laser irradiation, as well as the insensitivity of DND Raman spectra to surface chemistry, size, and transient structural changes.

Electronic Transitions in a Classical Antiferroelectric Banana-Shaped Compound

2010 ◽  
Vol 428-429 ◽  
pp. 317-321
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Liquid Crystal ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Ethyl Alcohol ◽  
Electronic Structures ◽  
Tight Binding ◽  
Methyl Benzoate ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Dilute Solutions

The electronic transitions in a classical banana-shaped liquid crystal 1,3-phenylene-bis [4-(4-octylphenylimino) methyl] benzoate have been investigated by measuring its optical absorption spectra in dilute solutions of ethyl alcohol and by calculating its electronic structures with extended Hückel tight binding program. The banana-shaped compound shows strong absorptions at 240, 280, 350 nm, respectively. On the basis of the calculated electronic structures, the three strong absorptions can be assigned to the *, n*, and nn* electronic transitions in this banana-shaped compound.

scholarly journals Growth, cultural and morphological characteristics of strains of Laetiporus sulphureus (Polyporales, Basidiomycota) under the influence of laser irradiation

2020 ◽  
Vol 77 (6) ◽  
pp. 472-479
Author(s):  
K.S. Reshetnyk ◽  
◽  
Yu.G. Prysedsky ◽  
Keyword(s):  
Laser Irradiation ◽  
Red Light ◽  
Green Light ◽  
Morphological Characteristics ◽  
Central Zone ◽  
Mycelium Growth ◽  
Laetiporus Sulphureus ◽  
Irradiation Energy ◽  
National University ◽  
532 Nm

The article provides growth, cultural and morphological characteristics of the vegetative mycelium on agar nutrient medium under the influence of laser irradiation for three strains of Laetiporus sulphureus from the Collection of basidiomycete cultures of the Department of Botany and Ecology of Vasyl' Stus Donetsk National University. The study was performed on potatoglucose agar (PGA) at a temperature of 26 ± 1 °C. It has been found that cultural and morphological characteristics of the colonies and the radial rate of their growth depend on the duration of irradiation (5 and 10 s) and the wavelength of light – green (532 nm), blue (405 nm) and red light (635 nm). For all studied strains of L. sulphureus, the most effective irradiation is that with green light (irradiation energy 51.1 mJ/cm2) lasting 10 s. Under the influence of this regime, the rate of radial mycelium growth increased from 23.4% to 66.7%, respectively, and the inoculum and the central zone of the surrounding colony formed a denser and higher mycelium of a pale sandy color. In general, the cultural and morphological features of the mycelial colonies of L. sulphureus strains under different conditions were somewhat different, but they were typical for this species.

scholarly journals Stimulation of TRPV1 by Green Laser Light

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Quanbao Gu ◽  
Lina Wang ◽  
Fang Huang ◽  
Wolfgang Schwarz
Keyword(s):  
Laser Irradiation ◽  
Cell Activation ◽  
Laser Light ◽  
Green Light ◽  
Medical Application ◽  
Green Laser ◽  
Ruthenium Red ◽  
Mast Cell Activation ◽  
Acupuncture Points ◽  
Stimulation Of

Low-level laser irradiation of visible light had been introduced as a medical treatment already more than 40 years ago, but its medical application still remains controversial. Laser stimulation of acupuncture points has also been introduced, and mast-cells degranulation has been suggested. Activation of TRPV ion channels may be involved in the degranulation. Here, we investigated whether TRPV1 could serve as candidate for laser-induced mast cell activation. Activation of TRPV1 by capsaicin resulted in degranulation. To investigate the effect of laser irradiation on TRPV1, we used theXenopusoocyte as expression and model system. We show that TRPV1 can functionally be expressed in the oocyte by (a) activation by capsaicin (K1/2= 1.1 μM), (b) activation by temperatures exceeding 42°C, (c) activation by reduced pH (from 7.4 to 6.2), and (d) inhibition by ruthenium red. Red (637 nm) as well as blue (406 nm) light neither affected membrane currents in oocytes nor did it modulate capsaicin-induced current. In contrast, green laser light (532 nm) produced power-dependent activation of TRPV1. In conclusion, we could show that green light is effective at the cellular level to activate TRPV1. To which extend green light is of medical relevance needs further investigation.

Optical properties of pure graphene in various forms: a time dependent density functional theory study

RSC Advances ◽  
2014 ◽  
Vol 4 (92) ◽  
pp. 50606-50613 ◽  
Author(s):  
S. Chopra ◽  
L. Maidich
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Optical Absorption ◽  
Oscillator Strength ◽  
Density Functional ◽  
Time Dependent ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Dependent Density

Optical absorption in graphene nano-ribbons (GNRs) of various shapes and isomeric forms was studied using time dependent density functional theory based calculations. The highest oscillator strength was found for rectangular GNRs.

scholarly journals Influence of Laser Radiation on Optical Properties of Semiconductor Materials

2019 ◽  
Vol 20 (4) ◽  
pp. 384-390
Author(s):  
P.O. Gentsar ◽  
S.M. Levytskyi
Keyword(s):  
Optical Properties ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Semiconductor Materials ◽  
Surface Layers ◽  
Defective Structure ◽  
Before And After ◽  
532 Nm ◽  
Transmission And Reflection ◽  
Pulsed Laser Irradiation

In this paper, the transmission and reflection spectra of n-Si(100) single crystals are measured; n-GaAs(100); solid solutions of Ge1-хSiх (х = 0.85) in the range (0.2 - 1.7)·10-6 m before and after laser irradiation at the wavelength λ = 532 nm. It is established that the main mechanism of influence of pulsed laser irradiation on the optical properties of thin surface layers of the investigated crystals is structural gettering, that is, the absorption due to the presence of sections of semiconductors that have a defective structure and have the ability to actively absorb defects and points.

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