High-performance silver-dielectric interference filters for RGBIR imaging

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Traditional red-green-blue (RGB) imaging systems for complementary metal-oxide-semiconductor (CMOS) sensors often require external infrared (IR)-cut filters.
• Organic color filters have limitations in performance and integration capabilities for advanced imaging.

Purpose of the Study:

• To investigate novel interference silver-dielectric multilayer filter architectures for high-performance RGB imaging.
• To develop integrated multispectral filters that eliminate the need for external IR-cut filters.

Main Methods:

• Design and optimization of interference silver-dielectric multilayer filters inspired by induced transmission principles.
• Fabrication and characterization of wafer-scale prototypes with sub-micrometer thickness filter stacks.

Main Results:

• Achieved combined colorimetric, signal-to-noise ratio, and sensitivity performances comparable to traditional organic color filters.
• Demonstrated the elimination of the external IR-cut filter requirement, enabling integration of additional channels (e.g., white, IR).
• Successfully patterned RGBIR filters down to 1.4 μm adjacent pixels with up to 80% transmission.

Conclusions:

• The novel interference filters provide a unique solution for fully integrated, high-performance multispectral filters in compact pixel sizes.
• These filters enhance imaging capabilities by allowing for additional spectral channels alongside RGB.
• The sub-micrometer thickness and high transmission offer significant advantages for miniaturized and advanced imaging systems.