Plasma-based deposition and processing techniques for optical fiber sensing

Abstract

Plasma-based techniques are widely applied for well-controlled deposition, etching or surface functionalization of a number of materials. It is difficult to imagine fabrication of novel microelectronic and optoelectronic devices without using plasma-enhanced deposition of thin films, their selective etching or functionalization of their surfaces for subsequent selective binding of chemical or biological molecules. Depending on the process parameters, i.e., generator frequency and power, composition of gases, pressure, temperature, and applied substrates, different effects of the process can be obtained. The chapter discusses current trends in application of plasma-based techniques for fabrication of novel optical sensing devices. Fabrication of materials with different structure (from amorphous to crystalline, porous, and multilayers), optical properties (absorption, refractive index), and surface activity, as well as their processing are reviewed. Application of the plasma methods enhancing sensing properties of various optical fiber sensing structures, namely long-period gratings, intermodal interferometers based on photonic crystal fiber, sensing structures based on lossy mode resonance or stacks of nano-films are given as examples and are discussed.