Ultra-High-Density Microscale Quick Response Codes: Integrating Color Multiplexing and Spectroscopic Encoding via Two-Photon Lithography

Rising demands for miniaturized, high-capacity data carriers have catalyzed the transformation of quick response (QR) codes into multifunctional platforms, enabling expanded storage capabilities without scaling up the size. We present a microscale, color-multiplexed QR code system fabricated via two-photon lithography, integrating spatial geometry, Raman-active perylene dyes, and multichannel color encoding within 15 μm modules. This platform achieves ∼1.77 × 10139 bits/mm2 data density while enabling orthogonal optical readouts with high fidelity. Our strategy offers a secure and artificial intelligence (AI)-compatible framework for next-generation data storage and anticounterfeiting technologies.