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James A. Lock

Bio: James A. Lock is an academic researcher from Cleveland State University. The author has contributed to research in topics: Scattering & Light scattering. The author has an hindex of 35, co-authored 141 publications receiving 3666 citations.


Papers
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Journal Article
TL;DR: In this article, the generalized Lorenz-Mie theory describes electromagnetic scattering of an arbitrary light beam by a spherical particle and the computationally most expensive feature of the theory is the evaluation of the beam-shape coefficients, which give the decomposition of the incident light beam into partial waves.
Abstract: Generalized Lorenz-Mie theory describes electromagnetic scattering of an arbitrary light beam by a spherical particle. The computationally most expensive feature of the theory is the evaluation of the beam-shape coefficients, which give the decomposition of the incident light beam into partial waves. The so-called localized approximation to these coefficients for a focused Gaussian beam is an analytical function whose use greatly simplifies Gaussian-beam scattering calculations. A mathematical justification and physical interpretation of the localized approximation is presented for on-axis beams.

224 citations

Journal ArticleDOI
TL;DR: In this article, the generalized Lorenz-Mie theory describes electromagnetic scattering of an arbitrary light beam by a spherical particle and the computationally most expensive feature of the theory is the evaluation of the beam-shape coefficients, which give the decomposition of the incident light beam into partial waves.
Abstract: Generalized Lorenz–Mie theory describes electromagnetic scattering of an arbitrary light beam by a spherical particle. The computationally most expensive feature of the theory is the evaluation of the beam-shape coefficients, which give the decomposition of the incident light beam into partial waves. The so-called localized approximation to these coefficients for a focused Gaussian beam is an analytical function whose use greatly simplifies Gaussian-beam scattering calculations. A mathematical justification and physical interpretation of the localized approximation is presented for on-axis beams.

210 citations

Journal ArticleDOI
TL;DR: In this article, the contribution of complex rays and the secondary radiation shed by surface waves to scattering by a dielectric sphere are calculated in the context of the Debye series expansion of the Mie scattering amplitudes.
Abstract: The contributions of complex rays and the secondary radiation shed by surface waves to scattering by a dielectric sphere are calculated in the context of the Debye series expansion of the Mie scattering amplitudes. Also, the contributions of geometrical rays are reviewed and compared with the Debye series. Interference effects between surface waves, complex waves, and geometrical waves are calculated, and the possibility of observing these interference effects is discussed. Experimental data supporting the observation of a surface wave-geometrical pattern is presented.

163 citations

Journal ArticleDOI
TL;DR: Localized beam models have been particularly useful for speeding up numerical computations in the framework of generalized Lorenz-Mie theories (GLMTs), i.e. theories dealing with the interaction between electromagnetic arbitrary shaped beams and a regular particle, allowing one to solve the problem by using the method of separation of variables as discussed by the authors.
Abstract: The description of electromagnetic arbitrary shaped beams (e.g. laser beams) under expanded forms requires the evaluation of expansion coefficients known as beam shape coefficients. Several methods have been designed to evaluate these coefficients but the most efficient one relies on the use of localization operators, leading to localized approximations and to localized beam models, whose history and features are reviewed in this paper. Localized approximations and localized beam models have been particularly useful for speeding up numerical computations in the framework of generalized Lorenz–Mie theories (GLMTs), i.e. theories dealing with the interaction between electromagnetic arbitrary shaped beams and a regular particle, allowing one to solve the problem by using the method of separation of variables. However, they can be useful in other scattering approaches, such as the extended boundary condition method (or null-field method), or more generally, when the need of an efficient description of an electromagnetic arbitrary shaped beam is required.

158 citations

Journal ArticleDOI
TL;DR: In this article, the basic formulas of generalized Lorenz-Mie theory are applied to scattering of a focused Gaussian laser beam by a spherical particle and various applications of focused beam scattering are also described, such as optimizing the rate at which morphology-dependent resonances are excited, laser trapping, particle manipulation, and the analysis of optical particle sizing instruments.
Abstract: The basic formulas of generalized Lorenz–Mie theory are presented, and are applied to scattering of a focused Gaussian laser beam by a spherical particle. Various applications of focused beam scattering are also described, such as optimizing the rate at which morphology-dependent resonances are excited, laser trapping, particle manipulation, and the analysis of optical particle sizing instruments. Each of these applications requires either special positioning the beam with respect to the particle or illumination of only part of the particle by the beam.

128 citations


Cited by
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TL;DR: While the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice), and I believe that the Handbook can be useful in those laboratories.
Abstract: There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

2,493 citations

Journal ArticleDOI
TL;DR: Theoretical expressions of the radiation pressure force for a dielectric sphere in the Rayleigh regime of light scattering under illumination of a Gaussian laser beam with the fundamental mode are derived in explicit form as a function of measurable quantities of the beam parameter in MKS units as mentioned in this paper.

789 citations

Journal ArticleDOI
TL;DR: Not involving evanescent fields and not requiring mechanical scanning, photonic nanojets may provide a new means to detect and image nanoparticles of size well below the diffraction limit and yield a potential novel ultramicroscopy technique using visible light for detecting proteins, viral particles, and even single molecules.
Abstract: We report what we believe to be the first evidence of localized nanoscale photonic jets generated at the shadow-side surfaces of micronscale, circular dielectric cylinders illuminated by a plane wave These photonic nanojets have waists smaller than the diffraction limit and propagate over several optical wavelengths without significant diffraction We have found that such nanojets can enhance the backscattering of visible light by nanometer-scale dielectric particles located within the nanojets by several orders of magnitude Not involving evanescent fields and not requiring mechanical scanning, photonic nanojets may provide a new means to detect and image nanoparticles of size well below the diffraction limit This could yield a potential novel ultramicroscopy technique using visible light for detecting proteins, viral particles, and even single molecules; and monitoring molecular synthesis and aggregation processes of importance in many areas of biology, chemistry, material sciences, and tissue engineering

733 citations

Journal ArticleDOI
TL;DR: In this article, the basic properties of dielectric whispering gallery mode resonators are reviewed for applications of the resonators in optics and photonics, as well as their applications in communication networks.
Abstract: We briefly review basic properties of dielectric whispering gallery mode resonators that are important for applications of the resonators in optics and photonics.

731 citations