Terahertz Devices Using the Optical Activation of GeTe Phase Change Materials: Toward Fully Reconfigurable Functionalities

Multifunctional terahertz (THz) devices are crucial for the development of practical applications such as high-speed communications, spectroscopy, and imaging, but their expansion is still requiring efficient agility functions operating in the THz domain. Chalcogenide phase change materials (PCMs) with broadband responses and nonvolatile and reversible transitions between dielectric and metal-like phases were successfully investigated as agile elements in photonics or electronics applications, but their potential for controlling the THz waves is still under evaluation. We are demonstrating the optical control of specific states of the germanium telluride (GeTe) PCM and its integration as a control element for enabling future optically reconfigurable THz devices. The excellent contrast of the material's THz properties in the two dissimilar states was used for optical-induced modulation of THz resonances of a metamaterial based on split-ring-resonator metallic structures integrating GeTe patterns. We experimentally confirm for the first time the feasibility of all dielectric GeTe-based THz polarizers, presenting broadband responses, high extinction ratios when the GeTe is in the metal-like phase, and almost transparency when amorphous. This highly functional approach based on optically controlled multioperational THz devices integrating PCMs is extremely stimulating for generating future disruptive developments (field-programmable metasurfaces, dielectric coding metamaterials) with multifunctional capabilities for THz waves manipulation.

Automated summary

Chalcogenide phase change materials (PCMs) with broadband responses and nonvolatile and reversible transitions have been investigated for their potential in controlling THz waves. The optical control of specific states of germanium telluride (GeTe) PCM has been demonstrated, showing promise for future optically reconfigurable THz devices with high functionality. Experimentally confirmed all dielectric GeTe-based THz polarizers present broadband responses and high extinction ratios, indicating potential for future disruptive developments in THz wave manipulation.