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Paras N. Prasad - One of the best experts on this subject based on the ideXlab platform.
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave...
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.
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Nonlinear optical absorption and stimulated Mie Scattering in metallic nanoparticle suspensions
The Journal of chemical physics, 2013Co-Authors: Cheung Law, Alexander Baev, Sha Liu, Mark T. Swihart, Paras N. PrasadAbstract:The nonlinear optical properties of four metallic (Au-, Au/Ag-, Ag-, and Pt-) nanoparticle suspensions in toluene have been studied in both femtosecond and nanosecond regimes. Nonlinear transmission measurements in the femtosecond laser regime revealed two-photon absorption (2PA) induced nonlinear attenuation, while in the nanosecond laser regime a stronger nonlinear attenuation is due to both 2PA and 2PA-induced excited-state absorption. In the nanosecond regime, at input pump laser intensities above a certain threshold value, a new type of stimulated (Mie) Scattering has been observed. Being essentially different from all other well known molecular (Raman, Brillouin) stimulated Scattering effects, the newly observed stimulated Mie Scattering from the metallic nanoparticles exhibits the features of no frequency shift and low pump threshold requirement. A physical model of induced Bragg grating initiated by the backward Mie Scattering from metallic nanoparticles is proposed to explain the gain mechanism of the observed stimulated Scattering effect.
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stimulated Mie Scattering in nanocrystals suspension
Applied Physics Letters, 2012Co-Authors: Wing Cheung Law, Liwei Liu, Xihe Zhang, Paras N. PrasadAbstract:In this letter, we report the observation of backward stimulated Mie Scattering in a suspension of CdSe/Cds/ZnS nanocrystals in chloroform, pump by 816-nm or 1064-nm nanosecond laser pulses. The observed stimulated Scattering exhibits the features of no frequency-shift, low pump threshold requirement, and easy controllability. For average nanocrystals’ size of ∼5.5 nm and weight concentration of 4.5 mg/mL, the measured nonlinear reflectivity (energy conversion efficiency from pump pulse to stimulated Scattering pulse) could be up to 32%. This nanoparticles-based stimulated Scattering effect can find special applications for self-adapted bioimaging, high-sensitivity sensors, lasing feedback elements, and optical ranging and lidar systems.
Alexander Baev - One of the best experts on this subject based on the ideXlab platform.
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave...
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Nonlinear optical absorption and stimulated Mie Scattering in metallic nanoparticle suspensions
The Journal of chemical physics, 2013Co-Authors: Cheung Law, Alexander Baev, Sha Liu, Mark T. Swihart, Paras N. PrasadAbstract:The nonlinear optical properties of four metallic (Au-, Au/Ag-, Ag-, and Pt-) nanoparticle suspensions in toluene have been studied in both femtosecond and nanosecond regimes. Nonlinear transmission measurements in the femtosecond laser regime revealed two-photon absorption (2PA) induced nonlinear attenuation, while in the nanosecond laser regime a stronger nonlinear attenuation is due to both 2PA and 2PA-induced excited-state absorption. In the nanosecond regime, at input pump laser intensities above a certain threshold value, a new type of stimulated (Mie) Scattering has been observed. Being essentially different from all other well known molecular (Raman, Brillouin) stimulated Scattering effects, the newly observed stimulated Mie Scattering from the metallic nanoparticles exhibits the features of no frequency shift and low pump threshold requirement. A physical model of induced Bragg grating initiated by the backward Mie Scattering from metallic nanoparticles is proposed to explain the gain mechanism of the observed stimulated Scattering effect.
Shin-hyun Kim - One of the best experts on this subject based on the ideXlab platform.
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Selective Coloration of Melanin Nanospheres through Resonant Mie Scattering
Advanced Materials, 2017Co-Authors: Soojeong Cho, Tae Soup Shim, Ju Hyeon Kim, Dong-hyun Kim, Shin-hyun KimAbstract:Black melanin inks are prepared to selectively exhibit colors under strong light, inspired by human hair. High absorbance of melanin suppresses multiple Scattering, causing resonant Mie Scattering predominant. Various colors can be developed as the resonant wavelength dictated by nanosphere diameter. Therefore, the melanin inks can be used to encrypt and selectively disclose multicolor patterns for anticounterfeiting applications.
Loonseng Tan - One of the best experts on this subject based on the ideXlab platform.
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave...
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.
Ramamurthi Kannan - One of the best experts on this subject based on the ideXlab platform.
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave...
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mechanism of stimulated Mie Scattering light induced redistribution of self assembled nanospheres of two photon absorbing chromophore
Journal of Chemical Physics, 2019Co-Authors: Alexander Baev, Ramamurthi Kannan, Loonseng Tan, Paras N. PrasadAbstract:We report the observation of backward stimulated Mie Scattering (SMS) due to light-field induced spatial redistribution of self-assembled nanospheres of a two-photon resonant organic chromophore in water, pumped by ∼10-ns laser pulses of ∼816-nm wavelength. The pump-energy threshold for generating backward stimulated Scattering in such a system is remarkably lower than that in pure water. The gain of backScattering originates from an induced Bragg grating that reflects partial energy from the pump beam into the backward Mie Scattering beam. Based on the experimental fact that the time-delay of the SMS pulse onset depends on both the pump level and the viscosity of the solvent, a physical model of SMS generation is proposed. Our experimental results have shown that the major contribution to the formation of an induced Bragg grating is spatial redistribution of nanoparticles suspended in the liquid. These nanoparticles are driven by a force that is proportional to the intensity gradient of the standing-wave field resulting from interference between the forward pump beam and the backward Mie Scattering beam. When the nanoparticle motion is frozen in a gel-like medium, no SMS is observed, which experimentally supports the validity of the proposed physical model.