High-reflectivity Bragg mirrors for IR applications using novel chalcogenide hybrid inorganic/organic polymers (CHIPs) (Conference Presentation)

Bragg mirrors are 1D photonic crystals made of a periodic stack of high and low refractive thin film materials that reflect only a small bandwidth of the spectrum. Such high-reflective devices are commercially available in the visible spectrum at relatively low costs. Functional Bragg mirrors for IR applications are greatly desired, but there exist challenges due to the limited availability of inexpensive, high refractive index, and transparent IR materials. Here, we present the design of high reflectivity Bragg mirrors working in the near and mid-IR range. Our mirror designs use the refractive index values of novel ultrahigh refractive index IR materials known as chalcogenide hybrid inorganic/organic polymers (CHIPs). CHIPs are synthetized from an inverse vulcanization process for elemental sulfur and selenium as reported by the Pyun group [1]. We integrate the optical properties of these materials and those of different low refractive index materials to generate various Bragg mirror designs. The extinction coefficients derived from absorption plots are also taken into account to increase accuracy. The theoretical values for reflectivity, physical thickness, and optical bandwidth are reported, as well as preliminary experimental results. We also present changes in reflectivity and bandwidth due to layer thickness variability. These IR Bragg mirrors have applications in devices and industries which require the use of specific wavelengths in the near and mid-IR range, such as beam-splitters, filters, anti-reflection coatings, etc.