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M squared

About: M squared is a research topic. Over the lifetime, 7803 publications have been published within this topic receiving 100449 citations.


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Journal ArticleDOI
TL;DR: In this paper, a new type of solution of the paraxial wave equation is presented, which encompasses as limiting cases both the diffraction-free beam and the gaussian beam.

817 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an analytical approach to express any axisymmetric beam field in a simple analytical form, by superposition of Gaussian beams about the same axis but with beam waists of different sizes located at different positions along the axis.
Abstract: The diffraction field of a Gaussian planar velocity distribution is a Gaussian beam function under the condition (ka)2≫1. This property makes a series of Gaussian functions attractive as a possible base function set. The new approach presented enables one to express any axisymmetric beam field in a simple analytical form—the superposition of Gaussian beams about the same axis but with beam waists of different sizes located at different positions along the axis. A computer optimization is used to evaluate the coefficients, as well as the beam waists and their positions. The extreme case of a piston radiator is used to test the approach. Good agreement between a ten‐term Gaussian beam solution and the results of numerical integration (or analytical solution on axis) is obtained throughout the beam field: in the farfield, the transition region, and the nearfield. Discrepancies exist only in the extreme nearfield (<0.1 times the Fresnel distance). For surface velocity distributions that are less discontinuous...

588 citations

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate a technique for optical manipulation of micron-sized particles, including biological samples, using a zeroth-order Bessel light beam, which offers a non-diffracting focal line of light.

548 citations

Journal ArticleDOI
TL;DR: In this article, a quasi-monochromatic Gaussian laser beam propagating in atmospheric turbulence is examined by using a derived analytic expression for the cross-spectral density function.
Abstract: A partially coherent quasi-monochromatic Gaussian laser beam propagating in atmospheric turbulence is examined by using a derived analytic expression for the cross-spectral density function. Expressions for average intensity, beam size, phase front radius of curvature, and wave-front coherence length are obtained from the cross-spectral density function. These results provide a model for a free-space laser transmitter with a phase diffuser used to reduce pointing errors.

510 citations

Journal ArticleDOI
Herwig Kogelnik1
TL;DR: In this article, a theoretical analysis of Gaussian beam propagation in media where the refractive index and/or the gain constant varies quadratically with the distance from the optic axis is made.
Abstract: A theoretical analysis is made of Gaussian beam propagation in media where the refractive index and/or the gain constant varies quadratically with the distance from the optic axis. Use of a complex beam parameter simplifies the analysis. A differential equation for the complex beam parameter is deduced from the wave equation for the complex beam parameter is deduced from the wave equation, and various of its solutions are discussed. This includes a discussion of light propagation in media with a gain profile, which are found capable of supporting stationary beams of constant diameter.

510 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202343
2022110
202132
202038
201943
201864