Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Analysis of mode competition in unstable optical resonators(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2010-05-01) Guizar Sicairos, Manuel; Guizar Sicairos, Manuel; 200201The dynamic coupled modes (DCM) method has been applied to study the transverse mode competition in optical resonators. In this work a differential equation for the homogeneously saturating dynamic gain is included in the original dynamic coupled modes method, thus increasing its physical resemblance and allowing the retrieval of gain temporal evolution at every point within the lasing medium. This new model provides a more realistic temporal evolution of the mode competition and gain saturation within the resonator, which can give further information of spatial coherence properties. The temporal information becomes particularly valuable when the laser transient is a matter of interest or when a continuous wave steady output is never reached, as occurs in pulsed lasers. The application of the method to a typical CO2 unstable confocal resonator is fully described, results and their connection to relevant physical properties of gas lasers, such as spiking and relaxation oscillations are discussed. The new general formulation does not assume that lasing medium fills the optical cavity and is suitable for modeling the dependence of small-signal gain and power gain on the transverse and longitudinal coordinates, thus providing a valuable tool for design of lasers with particular spatial coherence or mode discrimination requirements. Results of the numerical implementation of the DCM method with dynamic gain are in very good agreement with experimental measurements reported previously.
- Bare cavity study of the unstable Bessel resonator with finite apertures for the generation of Bessel-like beams(Instituto Tecnológico y de Estudios Superiores de Monterrey, 01/05/2005) Hernández Aranda, RaÚl I.; Dr. Julio C. Gutiérrez Vega; Dr. Gustavo Rodríguez Morales; Dr. Rodolfo Rodríguez y MasegosaA detailed study of the unstable Bessel resonator is presented. The design of this cavity consists of a reflective axicon and a convex spherical output coupler. A matrix method analysis for the bare resonator is employed to extract the eigenmodes and eigenvalues of the cavity, which allows the retrieval of the fundamental and higher-order modes. Diffractive losses and relative phase shift behavior, in terms of both the varying radius of curvature of the output coupler and the cavity length, are studied with the matrix method and the Fox-Li algorithm. Direct comparison of the transverse mode profiles with a similar resonator employing a concave output coupler is performed, showing excellent agreement for large values of the radius of curvature. The effects of varying the aperture of the output coupler and the wedge angle of the axicon, on the transverse mode profiles and diffractive losses, are also considered.