Qinghua Song

A Flat Lens with Tunable Phase Gradient by Using Random Access Reconfigurable Metamaterial

The first demonstration of an optofluidic metamaterial is reported where resonant properties of every individual metamolecule can be continuously tuned at will using a microfluidic system. This is called a random-access reconfigurable metamaterial, which is used to provide the first demonstration of a tunable flat lens with wavefront-reshaping capabilities.

Tunable flat lens based on microfluidic reconfigurable metasurface

A tunable flat lens is demonstrated based on reconfigurable metasurface, which is realized via changing the phase gradient of the metasurface in sub-wavelength level. The sub-wavelength metamolecules are formed by enclosing a liquid metal plug within microfluidic cavities, which can be tuned by changing the geometry of the metamolecules. The tunable flat lens is consisted of soft material with controllable functionalities. In simulation, the tuning of the focal length from 5 λ to 7 λ is demonstrated as the proof of concept. This reconfigurable metasurface can be used as a standard guideline to design different electromagnetic wave manipulation systems in realizing the dynamic control of beam steering, anti-reflection and focusing functionalities etc.

Metafluidic metamaterial: a review

Abstract Metafluidic metamaterial is a metamaterial the optical response of which is dependent on fluid contributed metamolecules. The dependence originates either from a fluid background coupling to the metamolecule or from the resonance in a liquid structured metamolecule. Different liquid materials including water, liquid crystal, and liquid metals are applied to realize the metafluidic metamaterial. Sophisticated technologies like electric bias and microfluidic system have been used for active control of metafluidic metamaterials which provide a new platform for electromagnetic wave manipulation and metadevice realization. The liquid background and significant tunability of the metafluidic metamaterial promise numerous applications, such as material sensing, bio-detection, energy harvesting, and imaging, just to name a few.

A tunable metamaterial for wide-angle and broadband absorption through meta-water-capsule coatings

We report a tunable metamaterial for wide-angle and broadband absorption by tuning the height of meta-water-capsule through microfluidics. An 80% absorption is achieved within 67% bandwidth when the incident angle varies from 0° to 45°.

Tunable metamaterial lens array via metadroplets

In this paper, a tunable THz lens array based on reconfigurable metamaterials is reported. The metamaterial consists with 40 × 40 liquid metal microdroplets, in which the shape is tuned under different air pressures. The droplets are formed by injecting the liquid mercury into a pre-designed microchannel network and arranged to focus incident THz wave. The focus spot size can be tuned with different droplet geometries. As a result, a tunable THz lens is constructed and the smallest spot size of 0.54λ is achieved. The tunable metamaterial lens is realized through simple fabrication processes, which has potential applications in flat lens and imaging system.