Colloidal coatings for laser optics

Three-dimensional photonic crystals (PCs) are periodic materials with a modulated refractive index on a length-scale close to the light wavelength. This optical property allows the design of optical components like highly reflective mirrors. Moreover, these structured materials are known to have a high laser-induced damage threshold (LIDT) in the sub-nanosecond range compared with multi-layered dielectric mirrors. This property results from the use of only one high LIDT material (silica). The second material used in the layer stack is air (porosity). This work presents the development of 3D PCs with narrow-sized colloidal silica particles, produced by sol–gel process and deposited with Langmuir–Blodgett technique. Different syntheses routes have been investigated and compared regarding the optical properties of the PCs. Finally, a numerical modeling based on an ideal opal network with and without defect is used to support the experimental results.