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

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Traditional color filters often involve complex fabrication processes.
• Integrating diverse color filters onto a single chip presents significant challenges.
• Structural color filters offer a promising alternative with potential for miniaturization.

Purpose of the Study:

• To develop an improved, scalable method for fabricating chip-scale color filters.
• To demonstrate the generation of a wide spectrum of reflective colors using a novel cavity design.
• To explore the integration of these filters onto flexible substrates for advanced applications.

Main Methods:

• Fabrication of stepwise metal-insulator-metal (MIM) Fabry-Pérot (FP) cavities.
• Utilizing a silver mirror, a SU8 gap layer of controlled thickness, and a thin nickel layer.
• Employing a simple ultraviolet (UV) lithography process for filter fabrication.

Main Results:

• Successful generation of reflective colors ranging from red to blue.
• Demonstration of filter fabrication on flexible substrates.
• Achieved large-scale filter arrays through a simplified processing technique.

Conclusions:

• The developed MIM FP cavity approach offers an efficient method for on-chip color filter integration.
• The process is scalable and adaptable for producing diverse color filter arrays.
• This technology holds potential for applications in advanced displays and sensing devices, including wearables.