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Theoretical Design for Dielectric Chirped Mirrors | ||
| Journal of College of Education | ||
| Article 1, Volume 0, Issue 3, 2017, Pages 27-44 | ||
| Author | ||
| Elham Jasim Mohammad | ||
| Abstract | ||
| This paper is concerned with theoretical study on optoelectronics physics to design dielectric chirped mirrors. Their theoretical analysis generally relies on the well-known scattering matrix formalism derived from the Maxwell equations. Laser performance strongly depends on the quality of optical coatings: reflectance of high reflectors should approach the ideal 100% value at the operation wavelengths in order to minimize laser intracavity losses and output coupling has to be set to specific values to ensure optimal operation. This paper reports a theoretical design of chirped mirror to achieve high reflectivity and dispersion compensation over a broad bandwidth. Analytic expressions for reflectivity, group delay and group delay dispersion are used. The aim is to compress the limits of pulse duration to reach femtosecond scale. The idea of chirped mirrors is based on the quarter-wave stack concept as a building block of dielectric high reflector. The quarter wave stack cannot be used in general as a dispersion element, therefore, a modulation of periodical structure are introduced in order to achieve the desired group delay dispersion. Dielectric materials TiO2/SiO2 arranged as a periodic stack have been used to design chirped mirrors using the Fused Silica as a substrate. In this paper we demonstrate a chirped dielectric multilayer mirror with controlled reflectivity and dispersion in the wavelength range 650 900nm, it exhibits a reflectivity of >99.98%. Furthermore, group delay dispersion shows monotonic behavior within wavelength range. | ||
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