Person: Encinas Sanz, Fernando
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First Name
Fernando
Last Name
Encinas Sanz
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
8 results
Search Results
Now showing 1 - 8 of 8
- PublicationSpatial characterization of the transversal structure of rotationally symmetric pulsed beams(Chapman & Hall Ltd., 1997-09) Encinas Sanz, Fernando; Serna Galán, Julio; Mejías Arias, Pedro Miguel; Martínez Herrero, Rosario; Martínez, C.A simple analytical model is proposed to describe the transversal spatial structure of a tridimensional rotationally symmetric pulsed beam. The spatial behaviour of the pulse amplitude is shown to be linked to its (measurable) second- and higher-order intensity moments, namely, beam width, quality parameter and kurtosis. As an illustrative experimental example, this model has been applied to high-quality TEA CO_2 laser pulses
- PublicationTime-varying beam quality factor and mode evolution in TEA CO_2 laser pulses(IEEE-Inst Electrical Electronics Engineers Inc., 1998-10) Serna Galán, Julio; Martínez, C.; Encinas Sanz, Fernando; Martínez Herrero, Rosario; Mejías Arias, Pedro MiguelThe time evolution of the transversal modes in a TEA CO_2 laser cavity has been investigated from the analysis of the time-varying beam quality factor M^2 of the emitted pulses. The experiments reveal a significant change in this parameter during the pulse evolution, which can be translated into an evolution of the modes of the laser cavity to reach a nearly stationary behavior. Attention is focused on both the appearance of a particular mode and the duration of its growing process.
- PublicationTime-resolved spatial profile of TEA CO_2 laser pulses: influence of the gas mixture and intracavity apertures(Optical Society of America, 2001-07) Serna Galán, Julio; Encinas Sanz, Fernando; Martínez Herrero, Rosario; Martin Mejías, PedroThe evolution of the intensity profile of transversely excited atmospheric CO_2 laser pulses is investigated within the intensity moment formalism. The beam quality factor M_2 is used to study the mode evolution. Attention is focused on the influence of both the gas mixture (N_2:CO_2:He) and the diameter of an intracavity diaphragm placed to attenuate higher-order modes. The degree of accuracy that can be attained by approximating the laser field amplitude by means of the lower-order terms of a Hermite-Gauss expansion is also analyzed. In particular, a bound for the truncation error is given in terms of two time-resolved spatial parameters, namely the beam width and the M_2 parameter.
- PublicationOn the parametric characterization of the transversal spatial structure of laser pulses(Elsevier Science B.V., 1997-07-01) Serna Galán, Julio; Martínez, C.; Encinas Sanz, Fernando; Martínez Herrero, Rosario; Mejías Arias, Pedro MiguelFrom the application of a simple analytical model to describe a laser pulse, the transversal spatial structure of the pulse amplitude is linked to its (measurable) second-order intensity moments, integrated along the pulse duration. These formulae are applied to some examples. The experimental values correspond to TEA CO_2 laser pulses, for which the dependence of the beam quality on the presence of nitrogen in the gas mixture and also on the size of an intracavity diaphragm has also been investigated.
- PublicationComplete spatial characterization of a pulsed doughnut-type beam by use of spherical optics and a cylindrical lens(Optical Society of America, 2001-07) Serna Galán, Julio; Encinas Sanz, Fernando; Nemes, GeorgeA complete spatial characterization (in second-order moments) of a doughnut-type beam from a pulsed transversely excited atmospheric CO_2 laser is described. It includes the measurement of the orbital angular momentum carried by the beam. The key element in the characterization is the use of a cylindrical lens in addition to the usual spherical optics. Internal features of the beam that would have remained hidden if only spherical optics were employed were revealed by use of the cylindrical lens. The experimental results are compared and agree with a theoretical Laguerre-Gauss mode beam
- PublicationTime-resolved spatial structure of TEA CO_2 laser pulses(Kluwer Academic Publishers, 2000-01) Serna Galán, Julio; Encinas Sanz, Fernando; Martínez Herrero, Rosario; Mejías Arias, Pedro MiguelThe evolution of the intensity profile of TEA CO_2 laser pulses along the pulse length is investigated both analytically and experimentally. A simple scalar model of the pulse amplitude is introduced, which gives the loaded-cavity modes as a linear combination of bidimensional Hermite-Gauss functions. According to this model a number of equations are derived which link the time-varying spatial structure of the pulse to its time-resolved second-order intensity moments, namely, the beam width and the M^2 parameter.
- PublicationBeam quality of TEA CO_2 laser pulses: Influence of the gas mixture and of intracavity apertures(SPIE--The International Society for Optical Engineering, 1996) Serna Galán, Julio; Martínez, C.; Martínez Herrero, Rosario; Encinas Sanz, Fernando; Mejías Arias, Pedro MiguelWe investigate from both a theoretical and an experimental point of view the dependence of the spatial parameters (integrated along the pulse length) of TEA CO_2 laser pulses on the presence of nitrogen in the gas mixture and also on the size of an intracavity diaphragm used to attenuate higher-order modes.
- PublicationEstudio y desarrollo de láseres pulsados de gas de excitación transversal(Universidad Complutense de Madrid, Servicio de Publicaciones, 2002) Encinas Sanz, Fernando; Guerra Pérez, José ManuelEl trabajo recoge el estudio y desarrollo de láseres pulsados de alta potencia y energía excitados transversalmente. Dentro de la amplia variedad de láseres que se incluyen en dicha clasificación, nuestros estudios se han centrado en dos de ellos: láser tea de co2 y láser te de n2. El interés de estos láseres radica en la gran variedad de aplicaciones de carácter científico y tecnológico que poseen. Algunas de las aportaciones originales de la tesis se mencionan a continuación: clarificación del papel del condensador de acoplo directo en el circuito de excitación del láser de co2 y su relación con la descarga de preionización y la descarga difusa de bombeo; se ha descubierto un nuevo efecto fotovoltaico inducido por el pulso de láser de co2 en junturas de semiconductores; se ha encontrado un nuevo tipo de fluctuaciones caóticas locales en la dinámica multimodo del láser de co2; así mísmo, los niveles de energía alcanzados con el láser de n2(uv e ir) son los mas altos de la literatura.