Advancements in Visible Reflection Coatings: Thin Films for Photonic and Optoelectronic Applications

TiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/SiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> multilayer structures, have demonstrated reflectance exceeding 90% in the visible spectrum (500–600 nm) and a contact angle of 45°, indicating strong hydrophilic self-cleaning properties. These coatings exhibit well-defined multilayers, with precise thickness control (~100–120 nm TiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>, ~80–100 nm SiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>), enhancing constructive interference and Bragg reflection for improved optical efficiency. XRD analysis confirmed the anatase phase of TiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>, optimizing crystallinity and mechanical stability, while FTIR spectroscopy validated Si-O-Ti bonding, ensuring strong interfacial adhesion. These properties make the coatings highly effective for integration into silicon photonics, waveguides, and optoelectronic devices, reducing optical losses and improving energy efficiency. Their application spans next-generation augmented reality displays, self-cleaning solar panels, high-efficiency dielectric mirrors, and low-loss reflectors for photonic circuits. With their potential for scalable manufacturing and enhanced durability, these coatings represent a significant advancement in energy-efficient optical systems, paving the way for more sustainable and high-performance photonic technologies.