High sulfur content photo-bleached polymer waveguides for mid-infrared optical applications (Conference Presentation)

For the first time, a high sulfur content polymer has been photo-bleached to yield an optical waveguide suitable for mid-wave infrared (MWIR) photonics. The polymer was synthesized by inverse vulcanization of elemental sulfur with the organic monomer 1,3-diisopropenylbenzene (DIB) to produce the polymeric material poly(sulfur-r-(1,3-diisopropenylbenze)) (poly(s-r-DIB)). This glassy, red polymer is available in bulk/solution form and affords easy processability. This novel polymer is extremely low cost, displays high refractive index (1.8), and is transparent at most short-wave infrared (SWIR) and MWIR wavelengths. These attributes make it highly desirable and a more suitable substitute to commercially available alternatives, such as chalcogenide glasses, which can be toxic, expensive and difficult to process. In this work, we demonstrate that photo-bleaching of the polymer occurs when exposed to intense UV light, inducing a change in the refractive index. The index can thereby also be tuned by changing the exposure parameters and the ambient atmospheric conditions. This phenomenon was used to fabricate optical waveguides suitable for SWIR and MWIR wavelengths. Optical characterization of the waveguides was performed to measure the propagation losses of the material. The low cost of the material and the facile nature of the fabrication and processing enables high reproducibility making this system desirable for a multitude of photonic applications such as on-chip spectroscopy and frequency combs.