Intrinsically Chiral Metamaterials with Giant Optical Chirality via One‐Step Lithography

Abstract Intrinsically chiral metamaterials (ICMMs) exhibiting strong chiroptical responses are promising for chiral sensing and lasing. Streamlining the fabrication process of ICMMs while enhancing the dissymmetry factor ( g ‐factor) is essential to enable large‐scale production and deployment in multifunctional systems. Conventional approaches, such as multi‐step lithography or rotational deposition, are not only complex but also susceptible to fabrication inaccuracies that degrade chiroptical performance. Typically, these methods yield a g ‐factor of only 0.1, which limits their practical utility. Herein, a one‐step lithography strategy based on electron‐beam deposition is introduced. By leveraging the shadowing effect and surface diffusion kinetics during thin‐film growth, 3D ICMMs with diverse topological architectures are fabricated. This approach achieves a record‐high g ‐factor of 1.3 in the visible band. Both the g ‐factor and resonance wavelength can be tuned through geometric design. The versatility of this method is further demonstrated across multiple material systems. As proof of concept, a sensing platform incorporating racemic chiral metamaterials enhance the chiral signal of cysteine enantiomers by three orders of magnitude. These findings open new pathways for developing advanced ICMMs in biosensing and integrated photonics.