Optical switching of GeTe phase change materials for high-frequency applications

A Polarization Reconfigurable Patch Antenna in the Millimeter-Waves Domain Using Optical Control of Phase Change Materials

“…In this work, we propose a polarization reconfigurable antenna using the optical control of specific elements integrated within the antenna main body realized with phase change material (PCM). PCM-based technology has been recently proven to be an effective method for realizing high-frequency switches (including the millimeter-waves frequencies) by controlling the material's properties (from an insulating state to a metallic one) using optical or electrical excitations [12]- [22].…”

“…The integration of GeTe or GST (Ge 2 Sb 2 Te 5 ) phase change materials into high-frequency functions is based on their ability to change from an amorphous state, OFF (insulating phase material) to a crystalline state, ON (conductive phase material) following the application of a thermal, electrical or optical stimulus. These materials have a good power handling capability, low energy consumption, high OFF state isolation, low ON state losses and a factor of merit greater than the current semiconductor-based switching technologies, over large frequency domains (up to 70 GHz) [12]- [22]. The key advantage of PCM-based devices technology is the bi-stability, i.e., they do not require a permanent bias to be maintained in their ON or OFF state.…”

“…PCMs transformation from an amorphous to a crystalline state and inversely, requires controlled and precise heating and cooling conditions brought by optical or electrical activation [12]- [16]. Compared with previously reported electrical activation of phase change in GeTe materials requiring elaborate heating scheme and technologically-complexmaterial stacks (thin film resistors, thermal and dielectric barriers, PCM-active and passivation materials) [14]- [16], optical activation of PCMs materials [20]- [22] and high frequency devices [12], [13], using direct irradiation with short optical pulses, may be preferable from the point of view of device fabrication simplicity and its non-essential encapsulation/ packaging requirements.…”

“…Here, we propose for the first time a polarization reconfigurable antenna which is designed as a square metal patch excited by a microstrip line and incorporating a phase change material (GeTe) on each corner. The phase change of these GeTe patterns, between their insulating (OFF) and metallic (ON) states, is realized using direct laser irradiation [12], [13]. This will modify the overall geometry of the patch and, depending on the specific state of the GeTe elements, will allow the antenna to operate, repeatedly, with In the following, we will present the properties of the GeTe material and its phase changes using thermal and optical control, and the evaluation of the electrical properties of this material in the millimeter wave domain.…”

Optical Reconfigurable Terahertz Devices using Phase Change Materials

“…PCMs in the form of chalcogenides like GeTe or Ge2Sb2Te5-GST are fascinating materials due to their ability to be electrically or optically switched in a repeatedly, bi-stable manner between an amorphous (insulating state) to a crystalline (conducting state) using short DC current or laser pulses. The phase transition (crystalline to amorphous and opposite) is achievable at the nanosecond timescales [2]. The material's bi-stability and its broadband response (from DC to THz and optical frequencies) are key advantages of the PCMbased technology.…”