Photochromic Diarylethene‐doped SU‐8 for Rewritable Optics and Integrated Photonic Switching

ABSTRACT Photochromic materials offer dynamic modulation of optical properties, but their integration into lithographically defined photonic structures remains limited. Here, we report diarylethene (DAE)‐doped SU‐8 ( DAE‐SU‐8 ) thin films and waveguides as a CMOS‐compatible photochromic platform for light‐controlled integrated photonics. The DAE‐SU‐8 films exhibit reversible switching between colorless open‐ring isomer and colored closed‐ring isomer, thereby enabling rewritable optical patterning. High‐contrast images, QR codes, and diffraction gratings with micrometer‐scale resolution are demonstrated. Furthermore, lithographically patterned SU‐8 waveguides act as photo‐switchable variable optical attenuators, achieving tunable insertion loss exceeding 90 dB, and as Y‐branch structures that enable port‐selective attenuation. These results establish DAE‐SU‐8 as a versatile photochromic material system bridging rewritable optics with reconfigurable integrated photonic circuits, opening new opportunities for optical data storage, security encoding, and programmable integrated photonics.