Microfluid-based soft metasurface for tunable optical activity in THz wave

Area of Science:

• Optics and Photonics
• Materials Science
• Metamaterials

Background:

• Metasurfaces are typically planar and lack intrinsic chirality, limiting their ability to generate optical activity.
• Achieving tunable optical activity is crucial for advanced optical applications but remains challenging with conventional metasurfaces.

Purpose of the Study:

• To realize tunable optical activity in terahertz (THz) waves using a microfluid-based soft metasurface.
• To demonstrate a method for inducing chirality and controlling polarization rotation in a reconfigurable metasurface.

Main Methods:

• Fabrication of a soft metasurface using polydimethylsiloxane (PDMS) with chiral microchannels filled with liquid metal (Galinstan).
• Integration of a microfluidic pressure system to deform the planar metasurface into a 3D chiral structure by pumping glycerol.
• Characterization of polarization rotation at 0.19 THz as a function of glycerol volume.

Main Results:

• The soft metasurface successfully exhibited tunable optical activity upon deformation.
• A polarization rotation ranging from 0° to 14° at 0.19 THz was achieved by controlling the injected glycerol volume.
• The microfluidic system enabled simultaneous reconfiguration of all meta-atoms, demonstrating a tunable chiral response.

Conclusions:

• A novel microfluid-based soft metasurface enables tunable optical activity for terahertz waves.
• The ability to dynamically induce chirality through structural deformation opens new avenues for optical device design.
• This technology has potential applications in polarization microscopy, bio-detection, and material analysis.