Study the Design of Dielectric Chirped Mirror | ||
| Al-Mustansiriyah Journal of Science | ||
| Article 1, Volume 23, Issue 6, September 2012, Pages 159-172 | ||
| Author | ||
| Elham Jasim Mohammad | ||
| Abstract | ||
| The generation of ultrashort pulses, that are pulses in the order of picoseconds and femtosecond lasers contains optical coatings as important functional elements, e.g. high reflectors HR, output couplers (OC) and antireflection (AR) coatings. These optical elements are based on the interference phenomenon of light. 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. Dielectric materials TiO2/SiO2 arranged as a periodic stack have been used to design chirped mirrors using a Fused Silica as a substrate. In this paper we demonstrate a chirped dielectric multilayer mirror with controlled reflectivity and dispersion in the wavelength range , it exhibits a reflectivity of >99.995%. Furthermore, group delay dispersion shows monotonic behavior within the wavelength range. Keyword: Dielectric Mirror, Chirped Mirror, Group Delay, Group Delay Dispersion, Fresnel reflection, Reflectivity. | ||
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