  We are demonstrating the optical control of a specific state of the germanium
telluride (GeTe) phase change material and its integration as control element
for realizing extremely efficient optically reconfigurable THz devices. The
excellent contrast of the material THz electrical properties in the two
dissimilar states were used for optical-induced fast modulation of THz
resonances of a hybrid metamaterial based of arrays of split ring resonator
metallic structures integrating GeTe patterns. We experimentally confirm for
the first time the feasibility to develop all dielectric (metal free)
GeTe-based THz polarizers presenting a broadband response, a high extinction
ratio when the GeTe is in the metal-like phase (up to 16.5 dB) and almost
transparent when the material is in the amorphous phase. The presented highly
functional approach based on non-volatile, optically controlled
multi-operational THz devices integrating PCMs, is extremely stimulating for
generating disruptive developments like field-programmable metasurfaces or
all-dielectric coding metamaterials with multifunctional capabilities for THz
waves manipulation.
