Omnidirectional mirror coating design for infrared applications

• Published in: Thin solid films Vol. 492; no. 1; pp. 226 - 231
• Main Authors: Lusk, D., Placido, F.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.12.2005; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Multilayers; Optical coatings; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical design; Optical elements, devices, and systems; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optics; Physics; Reflectors; Multilayers; 42.79.F; Reflectors; 42.79.W; Optical design; 68.65; Optical coatings; 42.15.E; Polarization; Inorganic compounds; Fibonacci sequences; Refractive index; Optimization; Cathode sputtering; Omnidirectional vision; Silicon; 42.79.F Multilayers; Mirrors; Microwave radiation; Experimental study; Thickness; Reflectivity; Growth from vapor; Magnetrons; Silicon oxides; Preparation; Incidence angle
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.06.053

An omnidirectional mirror, with a reflectance ( R) of 99.5% for all angles of incidence and both polarisations, was designed from quasi-periodic dielectric stacks based on Fibonacci sequence (FS) by selecting appropriate materials for high and low refractive index layers. At R = 99.5%, the initial omnidirectional spectral range was found to be from 1437 to 1618 nm, which covers completely the telecommunications wavelength region and the S, C and L bands of the erbium doped fiber amplifier gain region. The individual layers within the FS have the same physical thickness, thus having non quarter-wave optical thickness at the centre wavelength. Optimisation from the initial design can expand the omnidirectional spectral region at R = 99.5%, as well as show a higher value of R over the initial omnidirectional spectral range. Deposition and characterisation of the mirror coating have taken place using microwave assisted direct current magnetron sputtering and various characterisation techniques.