Monolithic chip-scale structural color filters fabricated with simple UV lithography

We demonstrate an improved approach to integrate various color filters on a chip-scale by using stepwise metal-insulator-metal FP cavities. The cavity is composed of a thick silver mirror, an SU8 gap layer of controlled thickness, and a thin nickel layer. Reflective colors from red to blue can be generated from these filters through a simple UV lithography process. The filters were also fabricated on a flexible substrate which could be incorporated into wearable devices. This method can realize large-scale filter arrays with simple processing and may facilitate the use of structural color filters in displays and sensing.