Abstract
In this study, the film growth kinetics for near and mid-IR reflection enhancing CdS and PbS dielectric thin films in HGWs is experimentally established. Crucial fabrication parameters including solution concentrations, pH, and fluid velocity are optimized. The film thickness of these films in HGWs is studied as a function of deposition time and temperature. Through IR spectral response analysis, the dielectric thin film thicknesses were determined and found to have a strong linear time dependence. Accurate metal sulfide film growth models in HGWs were developed, allowing for direct determination of necessary deposition times to yield metal sulfide HGW thin film coatings having a desired response.
Highlights
Metal / dielectric coated hollow glass waveguides (HGWs) have been successfully employed in a variety of applications ranging from high-powered medical laser delivery to highly sensitive gas sensing requiring the low-loss transmission of infrared radiation
The present study focuses on the growth of cadmium sulfide (CdS) and PbS optical thin films in HGWs via the dynamic liquid phase deposition (DLPD) method commonly employed for the deposition of high quality optical thin films in HGWs up to five meters in length
We have taken into account dispersion and used this information to determine the film thickness for each experimental procedure as a function of deposition time. 4.1 Cadmium sulfide thin films To investigate the growth of CdS thin films on an Ag coated HGW, segments with CdS coating times ranging from 55 to 195 minutes in 15 minute intervals were collected and the first interference peak positions obtained from their spectral response
Summary
Metal / dielectric coated hollow glass waveguides (HGWs) have been successfully employed in a variety of applications ranging from high-powered medical laser delivery to highly sensitive gas sensing requiring the low-loss transmission of infrared radiation. These metal sulfide materials are of particular interest in the development of such a high reflectivity multilayer thin film structure due to their high IR transparency, refractive index contrast in the IR region (nCdS ≈2.28, nPbS ≈4.00), chemical and structural compatibility, and relatively consistent and controlled deposition methods [4]. This study expands on previous metal sulfide thin film deposition studies by optimizing the deposition procedures to improve film quality, film thickness variation and consistency, and achieving adequate film thicknesses for low-loss mid-IR transmission while focusing in detail on the effects of deposition time, precursor solution temperatures, and waveguide length on metal sulfide thin film growth [2,3,6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
