Flexible THz Carrier‐Envelope Phase Shifter Based on Metamaterials

Abstract

The ability to manipulate terahertz (THz) waveform is important for its applications. Despite rapid progress in metamaterials (MMs), the carrier‐envelope phase (CEP) control for THz pulse is still challenging due to its broadband feature. THz scanning tunneling microscope (THz‐STM), as an emerging technique combining both high temporal and spatial resolution, imposes additional requirements. Here, an ultra‐thin and flexible THz CEP shifter with five groups of different MM arrays is proposed. The CEP shifter is based on a specified split‐ring resonator with a pair of cross‐oriented gratings to enhance transmission efficiency. Simulation and experimental results show that the CEP of the THz pulse is modulated by passing through different MM arrays in turn, which can be shifted as high as 2π. The CEP shifter has good tolerance to wide‐angle oblique incidence and structural bending, which is expected to be used as a key component for THz‐STM. The structure of the CEP shifter has many potential applications, including THz wave focusing, beam‐steering, spatial phase modulation, and structured light generation.

Real-Space Sampling of Terahertz Waveforms Under Scanning Tunneling Microscope

“…To further validate the effectiveness of the TDFES method, a homemade THz CEP shifter was employed to manipulate the weak THz pulse Figure a illustrates the modified experimental setup that allows unidirectional transmission of the THz beam, a requirement for the application of a CEP device.…”

“…Evidently, the accuracy of this process heavily relies on the powerful gating of the strong pulse, a crucial aspect that we will delve into later. Furthermore, by utilizing the recently developed THz carrierenvelope phase (CEP) shifter, 34 CEP variations in the THz near-field waveforms are successfully observed within the tunnel junction. Moreover, the subnanometer spatial resolution of our sampling methodology has been validated through meticulous point-to-point waveform sampling on a gold step and imaging across an atom cluster on the Au(111) surface with the waveform peak.…”

Frontiers in Flexible and Shape-Changing Arrays

“…While LCD panels are not yet fully flexible, folding displays have already been demonstrated in smartphones and tablets. At higher frequencies (e.g., THz range), the flexible substrate itself is thick enough compared to the radiated wavelength that it is possible to synthesize meta-materials using various patterns etched onto the laminate metallization layer [85], as illustrated in Fig. 14(c).…”

Efficient and Continuous Carrier-Envelope Phase Control for Terahertz Lightwave-Driven Scanning Probe Microscopy

“…Precise control of the THz waveform profile can be achieved on the basis of THz waveguides, 22,23 total internal reflection, 24,25 the Gouy phase, 7,26−29 or metamaterials. 30 However, most of these implementations require active mechanical components in the THz path or are incompatible with collinear visible alignment beams. Instead, our approach relies on frustrated total internal reflection in a polymer prism using a metallic mirror to change the evanescent coupling.…”

“…Precise control of the THz waveform profile can be achieved on the basis of THz waveguides, , total internal reflection, , the Gouy phase, ,− or metamaterials . However, most of these implementations require active mechanical components in the THz path or are incompatible with collinear visible alignment beams.…”