Chiral Metamaterials

Chiral metamaterials are artificial structures whose unit cells are chiral — they cannot be superimposed on their mirror image. The source digest lists a large body of patents on such structures, overwhelmingly Chinese (CN) utility models and invention filings, with a smaller number of KR, TW, JP, WO and US entries. The list is a title inventory only: it gives no abstracts, no measured performance and no legal status, and does not distinguish granted patents from applications.

Mechanical metamaterials

The largest group concerns mechanical behavior, with recurring design motifs:

• Negative Poisson's ratio (auxetic) behavior — materials that expand laterally when stretched. Examples include CN121897689 (different-chirality spliced variable-stiffness negative Poisson's ratio structure), CN121111926 (chiral composite negative Poisson's ratio metamaterial), CN120828905 (negative Poisson's ratio metamaterial wedge-shaped bottom), CN112307663 (design method for a chiral metamaterial structure with predetermined negative Poisson's ratio characteristic), and CN120212178 (energy-absorbing 3D metamaterial with interactively combined positive and negative Poisson's ratio structures).
• Compression–torsion coupling — axial compression induces twist. Examples include CN121854550 (rigidity-variable compression-torsion chiral metamaterial cell based on integrated molding), CN115750643 (chiral mechanical metamaterial with compression torsion coupling and swelling torsion coupling), CN112820362 and CN214226520 (Z-shaped compression-torsion metamaterial structures), CN118274058 (3D four-chiral pressure-torsion metamaterial structure), and CN116026678 (torsion angle measuring clamp for compression torsion mechanical test of chiral mechanical metamaterials).
• Tension–torsion and compression–shear coupling — CN112045990 (chiral auxetic metamaterial with tension-torsion coupling), CN112049886 (chiral auxetic metamaterial with compression-shear coupling), CN109822981 (3D cellular metamaterial with local tension-torsion coupling effect), CN108386472 (vibration absorber based on tension-torsion coupling metamaterial structure).
• Impact and vibration absorption — CN122014779 (multi-directional impact-resistant paper-cut-origami synergistic metamaterial), CN120946728 (star-shaped chiral impact-resistant energy-absorbing metamaterial), CN121520328 (chiral metamaterial vibration reduction structure for high-speed train floor), CN118669642 (self-balancing chiral metamaterial pipeline for low-frequency vibration isolation), CN118998251 (topological chiral vibration reduction metamaterial structure controlled by gyroscope), CN119911034 (damping wheel of auxetic metamaterial sandwich thickness gradient structure).
• Variable stiffness and 4D printing — CN118815892 (variable stiffness unit, variable stiffness metamaterial and mechanical metamaterial), CN118287674 (4D printing chiral superstructure heterogeneous stacked anisotropic deformable bearing structure).
• Structural applications — CN120482348 (lightweight helicopter undercarriage based on mechanical metamaterial), CN117845805 (electric tower anti-collision device based on chiral mechanical metamaterial), CN119427808 (manufacturing method for space station protection structure), CN121676478 (reinforced hollow blade filled with chiral metamaterial lattice structure), CN121473229 and CN121451498 (tuned mass inertial dampers for arch bridge suspenders).

Acoustic metamaterials

• CN122245538 — construction method of a self-similar 2D chiral metamaterial with sound insulation and shock absorption functions.
• CN114724536 — underwater sound insulation metamaterial based on chiral structure.
• CN113808562 — 3D chiral acoustic metamaterial with high bearing capacity and low broadband vibration suppression performance.
• CN113806975 — structural design method of a chiral acoustic metamaterial plate.
• CN119479600 — pressure-contact chiral-negative Poisson's ratio regulation and control acoustic metamaterial.

Optical, terahertz and microwave metamaterials

• Polarization control — CN115020988 and CN115020989 (chiral metamaterial units and arrays for tunable multi-polarization and linear-circular polarization conversion), CN121332179 (bifunctional chiral super-structure surface switching polarization conversion and wave absorption), CN117767017 (dual-band polarization converter based on chiral metasurface), CN105140652 (chiral metamaterial micro unit with 90-degree polarization deflection), CN105137520 and CN104865628 (spiral metal chiral metamaterial circular polarizers), WO2017020791 and WO2017020792 (right- and left-handed circular polarisation conversion metamaterial thin films).
• Absorbers — CN121584271 (vanadium dioxide-based terahertz broadband chiral absorber, actively regulated), CN111490355 (terahertz chiral metamaterial wave absorber with flexible substrate), CN109786973 (chiral microwave absorbing metamaterial), CN120779504 (chiral metamaterial absorber for multifunctional sensing), CN223285279 (electromagnetic wave absorber with dynamically openable wave-transparent window).
• Circular dichroism — CN119944313 (flexible chiral metasurface with tunable circular dichroism and polarization conversion), KR101494326 (circular dichroism method and apparatus using negative index metamaterials).
• Sensing — CN120142235 (chiral metamaterial sensor based on vanadium dioxide), CN114034659 (chiral serine identification via S-shaped mirror-image terahertz metamaterial), CN110186872 (refractive index sensor), US2021373009 (plasmonic meta-surface molecular sensors).
• Devices — CN114236648 (optical diode based on asymmetric reflection of a single-layer external chiral metasurface), JP2021193437 (nonmagnetic waveguide-type isolator), CN113381277 (chiral metamaterial circular polarization laser), CN112558294 (micro-cavity with chiral polarization selectivity), CN121784870 (3D spiral metamaterial optical device for chiral resolution of vortex beam), CN120065383 (2D light path device based on hyperbolic anisotropic metamaterial), CN120262026 (total space vector vortex generator).

Materials used

• Vanadium dioxide (VO₂) appears repeatedly for actively tunable chiral absorbers and sensors (CN121584271, CN120142235, CN113285232).
• GST (Ge-Sb-Te) phase-change material is used for a controllable chiral structure with temperature control (CN111965849).
• Graphene appears in a laser-direct-writing chiral terahertz metamaterial (CN116565571) and a mid-infrared double-channel chiral tunable graphene metamaterial (CN110441926).
• Metallic glass appears in CN206799718 and CN107012409 (glassy metal with chiral microstructure).
• Liquid crystals appear in CN121673652 (chiral liquid crystal superstructure for luminous object charge regulation).
• Perovskite appears in CN121248153 (ternary coupling enhanced perovskite chiral metamaterial).

Flexoelectric metamaterials

Two patents exploit flexoelectricity — polarization arising from strain gradients — in chiral structures: CN121922271 (tetra-chiral structure-based flexoelectric metamaterial) and CN120145772 (anti-tri-chiral structure-based flexoelectric metamaterial).

Non-CN entries

• WO2026100850 — single-photon generator including metal nanoparticles having a chiral structure and a 2D transition-metal dichalcogenide layer.
• US202528376 — photodetector pixel, photodetector and methods of forming the same.
• US2014017480 — doped chiral polymer metamaterials.
• US2011141541 — active chiral photonic metamaterial.
• US2010141358 — chiral metamaterials.
• US2022290570 — discrete macroscopic metamaterial systems.
• TWI793952 — a mechanical metamaterial with improving compressive responses.
• KR20240160417 — manufacturing method of a metamaterial using deformation of a nucleic acid origami structure.
• KR20180085314 — quasi-planar chiral metamaterial.
• KR20160113339 — meshed chiral metamaterial.
• WO2013010071 — gyrotropic metamaterial structure.

Caveat

The source provides titles only. It cannot support any claim about device performance, manufacturability or legal status, and the reader should treat the list as a pointer inventory rather than evidence.