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Full-Text Articles in Physics
Optimization Of The Nanolens Consisting Of Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Optimization Of The Nanolens Consisting Of Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Physics Faculty Publications
Using a simple and intuitive analytical approach, we perform optimization of a nanolens composed of coupled metal nanoparticles capable of subwavelength focusing of light inside the narrow gap separating the particles. Specifically, we optimize the structure of two nanospheres of different sizes to achieve maximum field enhancement at an off-center position in the gap. We demonstrate that the nanolens of two or more spheres acts simultaneously as an efficient antenna with large dipole and an efficient cavity with small effective volume.
Theory Of Optical Emission Enhancement By Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Theory Of Optical Emission Enhancement By Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Physics Faculty Publications
We present an analytical “coupled mode” model explaining enhancement of emission by an emitter placed within complexes of metal nanoparticles and apply it for an important case of an emitter placed inside the gap of two coupled Au nanospheres. This approach has dual advantages of exposing the underling physics of the enhancement and revealing a straightforward path toward optimization.
Comparative Study Of Field Enhancement Between Isolated And Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Comparative Study Of Field Enhancement Between Isolated And Coupled Metal Nanoparticles: An Analytical Approach, Greg Sun, Jacob B. Khurgin
Physics Faculty Publications
We present an analytical model that takes into account the coupling between the surface plasmon modes in complex metal nanostructures. We apply this model to evaluate the field enhancement in the gap of two coupled Au metal spheres embedded in GaN dielectric and compare the result with that obtained by the single sphere. The results show additional improvement can be obtained in the gap depending on the width of the gap. This approach offers a clear physical insight for the enhancement and a straightforward method for optimization.
Impact Of High-Order Surface Plasmon Modes Of Metal Nanoparticles On Enhancement Of Optical Emission, Greg Sun, Jacob B. Khurgin, C. C. Yang
Impact Of High-Order Surface Plasmon Modes Of Metal Nanoparticles On Enhancement Of Optical Emission, Greg Sun, Jacob B. Khurgin, C. C. Yang
Physics Faculty Publications
We consider the impact of high-order surface plasmon modes supported by the metal nanoparticles on the efficiency enhancement of optical emission. Using the example of Au nanosphere embedded in the GaN dielectric, we show that for an emitter with certain original radiative efficiency, placing the emitter too close to the metal sphere does not always produce additional enhancement. Thus our model provides analytical treatment of the luminescence quenching and can be used to optimize both nanoparticle size and its separation from the emitter to yield maximum enhancement.
Impact Of Disorder On Surface Plasmons In Two-Dimensional Arrays Of Metal Nanoparticles, Jacob B. Khurgin, Greg Sun
Impact Of Disorder On Surface Plasmons In Two-Dimensional Arrays Of Metal Nanoparticles, Jacob B. Khurgin, Greg Sun
Physics Faculty Publications
We study the impact of disorder on the properties of surface plasmons (SP) in metal nanoparticle arrays and develop analytical expressions enabling us to ascertain the degree of localization and mixing between the SP states. We show that it might be advantageous to intentionally introduce a certain degree of disorder in order to engineer the improved sensors and detectors.
Practical Enhancement Of Photoluminescence By Metal Nanoparticles, Greg Sun, Jacob B. Khurgin, R. A. Soref
Practical Enhancement Of Photoluminescence By Metal Nanoparticles, Greg Sun, Jacob B. Khurgin, R. A. Soref
Physics Faculty Publications
We develop a simple yet rigorous theory of the photoluminescence (PL) enhancement in the vicinity of metal nanoparticles. The enhancement takes place during both optical excitation and emission. The strong dependence on the nanoparticle size enables optimization for maximum PL efficiency. Using the example of InGaN quantum dots (QDs) positioned near Ag nanospheres embedded in GaN, we show that strong enhancement can be obtained only for those QDs, atoms, or molecules that are originally inefficient in absorbing as well as in emitting optical energy. We then discuss practical implications for sensor technology.
Practical Limits Of Absorption Enhancement Near Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref
Practical Limits Of Absorption Enhancement Near Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref
Physics Faculty Publications
We consider the enhanced absorption of optical radiation by molecules placed in the vicinity of spherical metal nanoparticles in the realistic situation that includes perturbation of the optical field by the absorbing molecules. We show that there is an optimal nanosphere radius that gives the strongest enhancement for each combination of the number of absorbing molecules, their absorption strength, and their distance from the nanosphere surface and that the enhancement is strong only for relatively weak and diluted absorbers.
Electroluminescence Efficiency Enhancement Using Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref
Electroluminescence Efficiency Enhancement Using Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref
Physics Faculty Publications
We apply the “effective mode volume” theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays. Using the example of an InGaN/GaN quantum-well active region positioned in close proximity to Ag nanospheres, we show that while the enhancement due to isolated metal nanoparticles is large, only modest enhancement can be obtained with ordered array of those particles. We further conclude that random assembly of isolated particles holds an advantage over the ordered arrays for light emitting devices of finite area.