Hollow glass waveguides (HGWs) have been researched extensively for the efficient transmission of radiation over a
broad spectral range spanning from the visible region to the far-IR. One such HGW film structure consists of a metallic
substrate with overlaying multilayer dielectric thin film stack of alternating high and low refractive index films. The
optical properties of such multilayer thin film stacks are well established and provide a method for developing photonic
bandgap fibers with exceptionally low attenuation losses at a desired wavelength. Transmission losses can be minimized
in multilayer waveguides through two main approaches; either maximizing the number of alternating layer pairs or
maximizing the index contrast between adjacent films. In practice, it has been shown that for liquid-phase deposition-based
procedures, the former approach leads to compounding surface and interface roughness, negating the low-loss
advantage of a multilayer waveguide. Thus, this research focuses on maximizing index contrast between adjacent
dielectrics in an attempt to minimize the number of films required to achieve acceptable transmission characteristics both
in theory and in practice. In this study, multilayer waveguides are fabricated using three dielectric materials: silver
iodide, lead sulfide, and cyclic olefin copolymer. Through exploitation of their high index contrast, these materials are
used to develop low-film-count multilayer waveguides designed for enhanced transmission at both Er:YAG and CO2
laser wavelengths.
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