Antimatched Electromagnetic Metasurfaces for Broadband Arbitrary Phase Manipulation in Reflection.

Area of Science:

• Electromagnetics
• Materials Science
• Applied Physics

Background:

• Metasurfaces typically impart phase shifts limited to 0-2π.
• Existing metasurfaces have limitations in achieving significant time delays for electromagnetic waves.

Purpose of the Study:

• To demonstrate multiresonant metasurfaces capable of providing arbitrarily large, tunable time delays.
• To overcome the conventional phase limitations of metasurfaces for ultrawide bandwidth applications.

Main Methods:

• Emulating geometric resonances of 3D systems using effective material resonances on ultrathin metasurfaces.
• Developing a constructive procedure to define required sheet admittivities.
• Utilizing an antimatching condition with interleaved electric and magnetic Lorentzian resonances to achieve reflection-only operation.

Main Results:

• Multiresonant metasurfaces supply arbitrarily large, tunable time delays over ultrawide bandwidths.
• The proposed approach yields a linear phase response, preventing pulse shape distortion.
• Metasurfaces perfectly reflect broadband pulses with a prescribed, tunable group delay.

Conclusions:

• Ultrathin metasurfaces can emulate thick bulk structures for temporal applications.
• The demonstrated technology offers precise control over group delay without pulse distortion.
• This work opens new avenues for temporal manipulation of electromagnetic waves using metasurfaces.