Flexible THz Carrier-Envelope Phase Shifter Based on Metamaterials

摘要

The ability to manipulate terahertz (THz) waveform is important for its applications.Despite rapid progress in metamaterials (MMs), the carrier-envelopephase (CEP) control for THz pulse is still challenging due to its broadbandfeature. THz scanning tunneling microscope (THz-STM), as an emergingtechnique combining both high temporal and spatial resolution, imposesadditional requirements. Here, an ultra-thin and flexible THz CEP shifterwith five groups of different MM arrays is proposed. The CEP shifter is basedon a specified split-ring resonator with a pair of cross-oriented gratings toenhance transmission efficiency. Simulation and experimental results showthat the CEP of the THz pulse is modulated by passing through different MMarrays in turn, which can be shifted as high as 2π. The CEP shifter has goodtolerance to wide-angle oblique incidence and structural bending, which isexpected to be used as a key component for THz-STM. The structure of theCEP shifter has many potential applications, including THz wave focusing,beam-steering, spatial phase modulation, and structured light generation.