Bessel beam: Difference between revisions
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A Bessel beam is a beam of [[electromagnetic radiation]] whose [[intensity]] is described by a [[Bessel function]]. The most important property of these beams, in many [[optical]] applications, is that they are non-diffractive. This means that, as they |
A Bessel beam is a beam of [[electromagnetic radiation]] whose [[intensity]] is described by a [[Bessel function]]. The most important property of these beams, in many [[optical]] applications, is that they are non-diffractive. This means that, as they propagate, they do not [[diffract]] and spread out; this is in contrast to most types of beams, which will rapidly spread out after being focussed down to a small spot. Another property is that the beam itself is [[self-healing]], meaning that the beam can be partially obstructed at one point, but will re-form at a point further down the beam [[axis]]. These properties together make Bessel beams extremely useful to research in [[Optical Tweezers|optical tweezing]], as a narrow Bessel beam will maintain its required property of tight focus over a relatively long section of beam and even when partially [[occlusion|occluded]] by the dielectric particles being tweezed. |
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The [[mathematics|mathematical]] function which describes a Bessel beam is a solution of [[bessel|Bessel's]] differential equation, which itself arises from separable solutions to [[Laplace's equation]] and the [[Helmholtz equation]] in cylindrical coordinates. |
The [[mathematics|mathematical]] function which describes a Bessel beam is a solution of [[bessel|Bessel's]] differential equation, which itself arises from separable solutions to [[Laplace's equation]] and the [[Helmholtz equation]] in cylindrical coordinates. |
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Revision as of 18:38, 6 February 2007
A Bessel beam is a beam of electromagnetic radiation whose intensity is described by a Bessel function. The most important property of these beams, in many optical applications, is that they are non-diffractive. This means that, as they propagate, they do not diffract and spread out; this is in contrast to most types of beams, which will rapidly spread out after being focussed down to a small spot. Another property is that the beam itself is self-healing, meaning that the beam can be partially obstructed at one point, but will re-form at a point further down the beam axis. These properties together make Bessel beams extremely useful to research in optical tweezing, as a narrow Bessel beam will maintain its required property of tight focus over a relatively long section of beam and even when partially occluded by the dielectric particles being tweezed.
The mathematical function which describes a Bessel beam is a solution of Bessel's differential equation, which itself arises from separable solutions to Laplace's equation and the Helmholtz equation in cylindrical coordinates.