High-Performance Optical Power Limiting Filters at Telecommunication Wavelengths: When Aza-BODIPY Dyes Bond to Sol–Gel Materials

An optical power limiter (OPL) device can change its optical properties depending on the input light intensity: it is ideally transparent at low incident power and presents a decrease in transmission when the incident intensity increases. This phenomenon can be used for protection of optical sensors. This paper presents the design of a functionalized aza-BODIPY chromophore, combining good nonlinear two-photon absorption and exited-state absorption in the short-wave infrared range (1300–1600 nm). The aza-BODIPY chromophores also show excellent thermal and photochemical stabilities. Their covalent grafting to a sol–gel matrix leads to the formation of class II sol–gel materials that allows for extraordinary doping concentrations of up to 280 mol·L–1 (40 wt %), which results in highly efficient OPL performances at 1550 nm.