Generación y aplicación de haces Bessel en trabajos de alineación.

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Bibliographic Details
Title:	Generación y aplicación de haces Bessel en trabajos de alineación.
Authors:	Gale, D. M.¹ dgale@inaoep.mx
Source:	Revista Cubana de Física. 2010, Vol. 27 Issue 1, p28-33. 6p. 2 Diagrams, 1 Chart, 3 Graphs.
Subjects:	OPTICAL tooling, OPTICAL measurements, ELECTROMAGNETIC waves, BESSEL functions, ASTRONOMICAL instruments, EQUIPMENT & supplies
Abstract (English):	The divergence of a Gaussian laser beam is a limiting factor for optical alignment tasks at large distances. Bessel beams have almost zero divergence but are still not widely used. We discuss the construction of an alignment telescope based on Bessel beam generation using a commercial laser diode module. The Bessel beam is generated with conical or plano-convex lenses, and projected using a commercial CCD camera lens to extend the useful range of the beam. Our Bessel beams have diameters of between 0.5 -- 1mm over beam lengths of 15m, representing a six-fold improvement compared to Gaussian beams, while the transverse beam structure (Bessel pattern) provides an excellent alignment aid for use with beam target. Another advantage of Bessel beams is their self-regeneration property, which allows the use of multiple beam targets with minimum beam degradation. We are using our alignment telescopes with crosshair targets to align optical components in a large astronomical telescope, and can achieve precisions of tens of microns over distances of 20m using purely visual methods. [ABSTRACT FROM AUTHOR]
Abstract (Spanish):	La divergencia de un haz láser Gausiano es un factor limitante para trabajos de alineación óptica a distancias largas. Los haces Bessel demuestran casi nula divergencia pero no son muy conocidos todavía. Discutimos la construcción de un telescopio de alineación basado en la generación de un haz Bessel usando un modulo láser diodo comercial como fuente. Utilizamos lentes cónicas y plano-convexas para generar el haz, y luego proyectamos la zona Bessel con una lente de camera CCD para aumentar su distancia útil de trabajo. Nuestros haces Bessel tienen diámetros del orden de 0.5 -- 1mm a lo largo de 15 metros de distancia, un factor de 6 menos que un haz Gausiano, y adicionalmente su estructura transversal de anillos concéntricos (el patrón Bessel) nos proporciona una referencia muy fina contra la cual podemos alinear blancos con una gran precisión. Otra ventaja de los haces Bessel es la propiedad de auto regeneración del haz, que permite colocar múltiples blancos sin que se deteriore el proceso de alineación. Estamos empleando nuestros telescopios de alineación en combinación con blancos de cruz para alinear componentes ópticos de un telescopio astronómico, logrando una precisión de décimas de micras en distancias de 20 metros y utilizando solo el ojo y una lupa como herramienta adicional. [ABSTRACT FROM AUTHOR]
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Database:	MedicLatina

Description
Abstract:	The divergence of a Gaussian laser beam is a limiting factor for optical alignment tasks at large distances. Bessel beams have almost zero divergence but are still not widely used. We discuss the construction of an alignment telescope based on Bessel beam generation using a commercial laser diode module. The Bessel beam is generated with conical or plano-convex lenses, and projected using a commercial CCD camera lens to extend the useful range of the beam. Our Bessel beams have diameters of between 0.5 -- 1mm over beam lengths of 15m, representing a six-fold improvement compared to Gaussian beams, while the transverse beam structure (Bessel pattern) provides an excellent alignment aid for use with beam target. Another advantage of Bessel beams is their self-regeneration property, which allows the use of multiple beam targets with minimum beam degradation. We are using our alignment telescopes with crosshair targets to align optical components in a large astronomical telescope, and can achieve precisions of tens of microns over distances of 20m using purely visual methods. [ABSTRACT FROM AUTHOR]
ISSN:	02539268