Ohmic Dissipation-Assisted Complex Amplitude Hologram with High Quality

Tailoring the phase and amplitude of electromagnetic waves has drawn great attention in the microwave, terahertz, and even optics domains. However, the existing method for simultaneous control of these two essential properties suffers from inadequate efficiency and narrow bandwidth, especially for microwave devices. Here, a strategy of overcoming this difficulty is proposed by introducing the ohmic sheet into a Fabry-Perot-like cavity. The arbitrary phase modulation can be realized by changing the geometric parameters and the orientation of elliptical split resonance ring; via changing the intensity of ohmic dissipation, the amplitude can be continuously adjusted from 0 to 1. Its most significant advantage is arbitrary wide-band complex-amplitude modulation without introducing cross-polarization crosstalk and backward scattering field interference. To verify its feasibility, three phase-amplitude holographic imaging prototypes at 12, 14, and 16 GHz are designed. Both the simulated and measured results manifest the excellent performances of the proposed metasurface, demonstrating the excellent performances with a remarkable signal-to-noise ratio and low root-mean-square error. This proposed strategy provides an alternative method to control the phase and amplitude arbitrarily, which not only realizes high-quality holography but also paves a way for random beamforming and so on.