The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Oleg V Angelsky - One of the best experts on this subject based on the ideXlab platform.
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low temperature laser stimulated controllable generation of micro bubbles in a Water Suspension of absorptive colloid particles
Optics Express, 2018Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner HansonAbstract:A method is described for the generation of micrometer-sized vapor-gas bubbles in a Water Suspension containing absorptive pigment nanoparticles. The diluted Suspension (mean interparticle distance 20 μm) absorbs the continuous laser radiation (wavelength 808 nm), and each particle in the best illuminated volume (~10 × 10 × 200 μm3) serves as a bubble-nucleation center. The Suspension heating is inessential (several degrees above the room temperature) and the bubbles are formed mainly of the air gases dissolved in Water. The bubbles can stably exist within or near the illuminated area where their location is governed by the competition between thermal and optical forces and can be controlled via the laser beam parameters. The method enables controllable creation, support, prescribed transportation, and destruction of the bubbles. This can be useful in applications aimed at precise sorting, transportation, and delivery of species in nano- and micro-engineering as well as for biomedical studies.
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controllable generation and manipulation of micro bubbles in Water with absorptive colloid particles by cw laser radiation
Optics Express, 2017Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, S M KontushAbstract:Micrometer-sized vapor-gas bubbles are formed due to local heating of a Water Suspension containing absorptive pigment particles of 100 nm diameter. The heating is performed by CW near-infrared (980 nm) laser radiation with controllable power, focused into a 100 μm spot within a 2 mm Suspension layer. By changing the laser power, four regimes are realized: (1) bubble generation; (2) stable growth of the existing bubbles; (3) stationary existence of the bubbles and (4) the bubbles’ shrinkage and collapse. This behavior is interpreted based on the temperature conditions. The generation and evolution of single bubbles and ensembles of bubbles with controllable sizes and numbers is demonstrated. The bubbles are grouped within the laser-illuminated region and form quasi-ordered structures. They can easily be moved and transported controlled by the focal spot. The results are useful for applications associated with the precise manipulation, sorting and specific delivery in nano- and micro-engineering problems.
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self action of continuous laser radiation and pearcey diffraction in a Water Suspension with light absorbing particles
Optics Express, 2014Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:Water Suspension of light-absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities favorable for optical treatment of organic and biological objects. We study experimentally the phenomena emerging in a thin layer of such a medium under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self-diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities.
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self diffraction of continuous laser radiation in a disperse medium with absorbing particles
Optics Express, 2013Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:We study the self-action of light in a Water Suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams, it is possible to create controllable phase and amplitude gratings whose contrast, spatial and temporal parameters depend on the beams’ coherence and power as well as the interference geometry. The grating characteristics are investigated via the beams’ self-diffraction. The main mechanism of the grating formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles’ displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating dynamics and degradation. The results and approaches can be used for investigation of the thermal relaxation and kinetic processes in liquid Suspensions.
Steen Gruner Hanson - One of the best experts on this subject based on the ideXlab platform.
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low temperature laser stimulated controllable generation of micro bubbles in a Water Suspension of absorptive colloid particles
Optics Express, 2018Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner HansonAbstract:A method is described for the generation of micrometer-sized vapor-gas bubbles in a Water Suspension containing absorptive pigment nanoparticles. The diluted Suspension (mean interparticle distance 20 μm) absorbs the continuous laser radiation (wavelength 808 nm), and each particle in the best illuminated volume (~10 × 10 × 200 μm3) serves as a bubble-nucleation center. The Suspension heating is inessential (several degrees above the room temperature) and the bubbles are formed mainly of the air gases dissolved in Water. The bubbles can stably exist within or near the illuminated area where their location is governed by the competition between thermal and optical forces and can be controlled via the laser beam parameters. The method enables controllable creation, support, prescribed transportation, and destruction of the bubbles. This can be useful in applications aimed at precise sorting, transportation, and delivery of species in nano- and micro-engineering as well as for biomedical studies.
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controllable generation and manipulation of micro bubbles in Water with absorptive colloid particles by cw laser radiation
Optics Express, 2017Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, S M KontushAbstract:Micrometer-sized vapor-gas bubbles are formed due to local heating of a Water Suspension containing absorptive pigment particles of 100 nm diameter. The heating is performed by CW near-infrared (980 nm) laser radiation with controllable power, focused into a 100 μm spot within a 2 mm Suspension layer. By changing the laser power, four regimes are realized: (1) bubble generation; (2) stable growth of the existing bubbles; (3) stationary existence of the bubbles and (4) the bubbles’ shrinkage and collapse. This behavior is interpreted based on the temperature conditions. The generation and evolution of single bubbles and ensembles of bubbles with controllable sizes and numbers is demonstrated. The bubbles are grouped within the laser-illuminated region and form quasi-ordered structures. They can easily be moved and transported controlled by the focal spot. The results are useful for applications associated with the precise manipulation, sorting and specific delivery in nano- and micro-engineering problems.
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self action of continuous laser radiation and pearcey diffraction in a Water Suspension with light absorbing particles
Optics Express, 2014Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:Water Suspension of light-absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities favorable for optical treatment of organic and biological objects. We study experimentally the phenomena emerging in a thin layer of such a medium under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self-diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities.
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self diffraction of continuous laser radiation in a disperse medium with absorbing particles
Optics Express, 2013Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:We study the self-action of light in a Water Suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams, it is possible to create controllable phase and amplitude gratings whose contrast, spatial and temporal parameters depend on the beams’ coherence and power as well as the interference geometry. The grating characteristics are investigated via the beams’ self-diffraction. The main mechanism of the grating formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles’ displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating dynamics and degradation. The results and approaches can be used for investigation of the thermal relaxation and kinetic processes in liquid Suspensions.
Pedro J. J. Alvarez - One of the best experts on this subject based on the ideXlab platform.
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fullerene Water Suspension nc60 exerts antibacterial effects via ros independent protein oxidation
Environmental Science & Technology, 2008Co-Authors: Delina Y. Lyon, Pedro J. J. AlvarezAbstract:Buckminsterfullerene (C60) can form Water Suspensions (nC60) that exert toxic effects. While reactive oxygen species (ROS) generation has been implicated as the mechanism for mammalian cytotoxicity, we propose that nC60 exerts ROS-independent oxidative stress in bacteria, with evidence of protein oxidation, changes in cell membrane potential, and interruption of cellular respiration. This mechanism requires direct contact between the nanoparticle and the bacterial cell and differs from previously reported nanomaterial antibacterial mechanisms that involve ROS generation (metal oxides) or leaching of toxic elements (nanosilver).
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Effect of soil sorption and aquatic natural organic matter on the antibacterial activity of a fullerene Water Suspension
Environmental Toxicology and Chemistry, 2008Co-Authors: Dong Li, Q Ilin Li, Delina Y. Lyon, Pedro J. J. AlvarezAbstract:The present study investigated the association of a C60 Water Suspension (nC60) with natural organic matter, present as a soil constituent or dissolved in the Water column, and its effect on the antibacterial activity of nC60. Sorption of nC60 to soil reduced its bioavailability and antibacterial activity, and the sorption capacity strongly depended on the organic content of the soil. Adsorption of aquatic dissolved humic substances onto nC60 and possible subsequent reactions also were found to eliminate nC60 toxicity at humic acid concentrations as low as 0.05 mg/L. These findings indicate that natural organic matter in the environment can mitigate significantly the potential impacts of nC60 on microbial activities that are important to ecosystem health.
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antibacterial activity of fullerene Water Suspensions nc60 is not due to ros mediated damage
Nano Letters, 2008Co-Authors: Delina Y. Lyon, Mark R Wiesner, Lena Brunet, George W Hinkal, Pedro J. J. AlvarezAbstract:The cytotoxic and antibacterial properties of nC60, a buckminsterfullerene Water Suspension, have been attributed to photocatalytically generated reactive oxygen species (ROS). However, in this work, neither ROS production nor ROS-mediated damage is found in nC60-exposed bacteria. Furthermore, the colorimetric methods used to evaluate ROS production and damage are confounded by interactions between nC60 and the reagents, yielding false positives. Instead, we propose that nC60 exerts ROS-independent oxidative stress, thus reconciling conflicting results in the literature.
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effect of a fullerene Water Suspension on bacterial phospholipids and membrane phase behavior
Environmental Science & Technology, 2007Co-Authors: Jiasong Fang, Delina Y. Lyon, Mark R Wiesner, Jinping Dong, Pedro J. J. AlvarezAbstract:Several fullerene-based nanomaterials generate reactive oxygen species that can damage cells. In this study, we investigated the effect of buckminsterfullerene (C60) introduced as colloidal aggrega...
Peter P Maksimyak - One of the best experts on this subject based on the ideXlab platform.
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low temperature laser stimulated controllable generation of micro bubbles in a Water Suspension of absorptive colloid particles
Optics Express, 2018Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner HansonAbstract:A method is described for the generation of micrometer-sized vapor-gas bubbles in a Water Suspension containing absorptive pigment nanoparticles. The diluted Suspension (mean interparticle distance 20 μm) absorbs the continuous laser radiation (wavelength 808 nm), and each particle in the best illuminated volume (~10 × 10 × 200 μm3) serves as a bubble-nucleation center. The Suspension heating is inessential (several degrees above the room temperature) and the bubbles are formed mainly of the air gases dissolved in Water. The bubbles can stably exist within or near the illuminated area where their location is governed by the competition between thermal and optical forces and can be controlled via the laser beam parameters. The method enables controllable creation, support, prescribed transportation, and destruction of the bubbles. This can be useful in applications aimed at precise sorting, transportation, and delivery of species in nano- and micro-engineering as well as for biomedical studies.
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controllable generation and manipulation of micro bubbles in Water with absorptive colloid particles by cw laser radiation
Optics Express, 2017Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, S M KontushAbstract:Micrometer-sized vapor-gas bubbles are formed due to local heating of a Water Suspension containing absorptive pigment particles of 100 nm diameter. The heating is performed by CW near-infrared (980 nm) laser radiation with controllable power, focused into a 100 μm spot within a 2 mm Suspension layer. By changing the laser power, four regimes are realized: (1) bubble generation; (2) stable growth of the existing bubbles; (3) stationary existence of the bubbles and (4) the bubbles’ shrinkage and collapse. This behavior is interpreted based on the temperature conditions. The generation and evolution of single bubbles and ensembles of bubbles with controllable sizes and numbers is demonstrated. The bubbles are grouped within the laser-illuminated region and form quasi-ordered structures. They can easily be moved and transported controlled by the focal spot. The results are useful for applications associated with the precise manipulation, sorting and specific delivery in nano- and micro-engineering problems.
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self action of continuous laser radiation and pearcey diffraction in a Water Suspension with light absorbing particles
Optics Express, 2014Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:Water Suspension of light-absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities favorable for optical treatment of organic and biological objects. We study experimentally the phenomena emerging in a thin layer of such a medium under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self-diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities.
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self diffraction of continuous laser radiation in a disperse medium with absorbing particles
Optics Express, 2013Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:We study the self-action of light in a Water Suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams, it is possible to create controllable phase and amplitude gratings whose contrast, spatial and temporal parameters depend on the beams’ coherence and power as well as the interference geometry. The grating characteristics are investigated via the beams’ self-diffraction. The main mechanism of the grating formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles’ displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating dynamics and degradation. The results and approaches can be used for investigation of the thermal relaxation and kinetic processes in liquid Suspensions.
Ya A Bekshaev - One of the best experts on this subject based on the ideXlab platform.
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low temperature laser stimulated controllable generation of micro bubbles in a Water Suspension of absorptive colloid particles
Optics Express, 2018Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner HansonAbstract:A method is described for the generation of micrometer-sized vapor-gas bubbles in a Water Suspension containing absorptive pigment nanoparticles. The diluted Suspension (mean interparticle distance 20 μm) absorbs the continuous laser radiation (wavelength 808 nm), and each particle in the best illuminated volume (~10 × 10 × 200 μm3) serves as a bubble-nucleation center. The Suspension heating is inessential (several degrees above the room temperature) and the bubbles are formed mainly of the air gases dissolved in Water. The bubbles can stably exist within or near the illuminated area where their location is governed by the competition between thermal and optical forces and can be controlled via the laser beam parameters. The method enables controllable creation, support, prescribed transportation, and destruction of the bubbles. This can be useful in applications aimed at precise sorting, transportation, and delivery of species in nano- and micro-engineering as well as for biomedical studies.
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controllable generation and manipulation of micro bubbles in Water with absorptive colloid particles by cw laser radiation
Optics Express, 2017Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, S M KontushAbstract:Micrometer-sized vapor-gas bubbles are formed due to local heating of a Water Suspension containing absorptive pigment particles of 100 nm diameter. The heating is performed by CW near-infrared (980 nm) laser radiation with controllable power, focused into a 100 μm spot within a 2 mm Suspension layer. By changing the laser power, four regimes are realized: (1) bubble generation; (2) stable growth of the existing bubbles; (3) stationary existence of the bubbles and (4) the bubbles’ shrinkage and collapse. This behavior is interpreted based on the temperature conditions. The generation and evolution of single bubbles and ensembles of bubbles with controllable sizes and numbers is demonstrated. The bubbles are grouped within the laser-illuminated region and form quasi-ordered structures. They can easily be moved and transported controlled by the focal spot. The results are useful for applications associated with the precise manipulation, sorting and specific delivery in nano- and micro-engineering problems.
-
self action of continuous laser radiation and pearcey diffraction in a Water Suspension with light absorbing particles
Optics Express, 2014Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:Water Suspension of light-absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities favorable for optical treatment of organic and biological objects. We study experimentally the phenomena emerging in a thin layer of such a medium under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self-diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities.
-
self diffraction of continuous laser radiation in a disperse medium with absorbing particles
Optics Express, 2013Co-Authors: Oleg V Angelsky, Ya A Bekshaev, Peter P Maksimyak, A P Maksimyak, Steen Gruner Hanson, Yu C ZenkovaAbstract:We study the self-action of light in a Water Suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams, it is possible to create controllable phase and amplitude gratings whose contrast, spatial and temporal parameters depend on the beams’ coherence and power as well as the interference geometry. The grating characteristics are investigated via the beams’ self-diffraction. The main mechanism of the grating formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles’ displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating dynamics and degradation. The results and approaches can be used for investigation of the thermal relaxation and kinetic processes in liquid Suspensions.
