Photonic studies on polymer-coated sapphire-spheres: A model system for biological ligands

Silanization of Sapphire Surfaces for Optical Sensing Applications

“…9 For fiber optics, glass, diamond, and sapphire are probably the most relevant optical transparent interfaces according to their accessible electromagnetic windows. Due to the limited stability of glass in harsh environments, 4 diamond and sapphire have emerged as preferred substrates under such conditions owing to their chemical stability and mechanical robustness. 10 Sapphire is of particular interest in optical sensing applications, as the material is significantly less costly compared to diamond at almost comparable chemical and mechanical stability, next to transparency in a spectral region ranging from 200 to 5000 nm.…”

“…in chemo- or biosensors. In recent years, transparent transducer materials for optical chem/biosensing applications were increasingly adopted in the field of biosensing . Potential applications in optical sensing using these materials include mid-infrared (MIR) sensors based on attenuated total reflection (ATR), and biosensors based on microsphere resonators relying on resonant wavelength shifts during binding of analytes. − In particular, fiber optic ATR sensors enable analyzing binding events in real time via concentration-dependent attenuation of the evanescent field emanating at the interface between the optically denser waveguide made, e.g., from sapphire, and an optically thinner medium such as an aqueous analyte solution .…”