Proyectos
Broadband White Light Continuum (WLC) in Gases by using a Chamber and Hollow Core Photonics Crystal Fiber
Resumen
Frequencies broadening has been a great deal of research interest since its appearance in early 1960's in condensed media reported by Alfano and Shapiro [1]. A large number of experiments and new theories have been developed in order to explain the mechanism of this phenomenon called supercontinuum (SC) [2]. Supercontinuum generation occurs when narrow-band incident pulses undergo extreme nonlinear spectral broadening to produce a broadband (often a white light) spectrally continuous output. White-light continuum (WLC) generation in gases was first mentioned by Corkum et al. [3] and the physics involved in spectral broadening is still being investigated [4, 5] under the promise of being useful to applications as remote sensing [6], nonlinear spectroscopy [7] or Z-scan technique [8]. Our interest lies in using a single light beam source that contains a broadband spectrum with enough power that can replace conventional tunable sources of radiation as optical parametric generators/amplifiers (OPGs/OPAs). In several condensed media the enhancement of spectral broadening by using pump-seed interaction have been demonstrated [9, 10, 11], in terahertz regime [12], and even in gases [9, 13]. Since WLC generated in gases is not limited by the same energy restrictions of optical damage thresholds as condensed media, it is advantageous to use gas for high energy WLC generation. Gases have offered attractive features as media for nonlinear optics. Unlike solid-state materials, they are not susceptible to irretrievable optical damage at high intensities and their nonlinearity and dispersion can be easily tuned by changing the pressure and gas mixture. They also offer wider transparency windows than their solid-state counterparts. A wide range of nonlinear effects has been demonstrated, including supercontinuum generation, high-harmonic generation and filamentation [1, 2, 3]. Experiments in free space, however, are intrinsically awkward because they suffer from self-focusing effects at high laser powers and unavoidable diffraction, which causes a beam to spread out and its intensity to fall as it propagates. Furthermore, gases have much lower nonlinear coefficients than solids, which raise the threshold for nonlinear effects and increases the need to use long optical path lengths and high intensities. Longer path lengths result in diffraction becoming a major problem. But in bulk gases, higher-order nonlinear effects can sometimes be turned to good use. This situation can be handled by infiltrating the gases into a hollow core photonics crystal (HC-PCF) fiber which can reduce the refraction effects. In addition, HC-PCF infiltrated with gases have the possibility of creating optical soliton what contribute to generation of supercontinuum [14, 15]. . Our specific goal with this proposal is to study and produce a broadband WLC in inert gases such as Krypton and Fluor by using a chamber and a hollow core photonic cristal fiber, and to ensure stability of the beam profiles and intensities at various wavelengths. In both cases, they offer the possibility of tuning the generation of new frequencies by controlling the pressure [14].
Convocatoria
Nombre de la convocatoria:CONVOCATORIA NACIONAL DE PROYECTOS PARA EL FORTALECIMIENTO DE LA INVESTIGACIÓN, CREACIÓN E INNOVACIÓN DE LA UNIVERSIDAD NACIONAL DE COLOMBIA 2016-2018
Modalidad:Modalidad Única
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