Design,Numerical Simulation And Analysis Of GST-based Tunable Color Filters

Metal-based reflective color filters have been widely studied in the fields of color decoration,optical anti-counterfeiting and color printing due to their high-resolution,non-fading and non-polluting structure color devices.But so far,most of the research work have focused on static structural colors,which cannot meet the needs of social development.In recent years,it has become a new research hotspot to realize dynamic control of smart-material-based structure color devices which are sensitive to light,heat,electricity and other environments.By combining the Ge₂Sb₂Te₅?GST?phase change material and the Fabry-Perot?F-P?cavity,we systematically simulated and analyzed the optical properties and mechanism of GST/SiO₂/Al and Au/GST/SiO₂/Ag structures used in dynamic structure color devices.?1?We designed a tunable reflective color filter based on asymmetric F-P cavity,comprising of GST/SiO₂/Al three-layer thin film using a phase change material GST as the switchable ultrathin lossy layer.By numerical simulation and analytical analysis,we systematically studied the color tunability and switch mechanism of the planar thin film structure based structural color devices.The results showed that the spectrum selection characteristics of the color filter can be dynamically controlled through the reversible phase transition of GST from amorphous to crystalline,and the obtained color has high brightness,high saturation and wide color gamut.The designed structure can be applied in colorimetric sensing,smart windows,optical anti-counterfeiting and data security.?2?We designed and investigated the optical properties of a tunable reflective color filter composed of Au/GST/SiO₂/Ag four-layer film structure.Relying on the resonance behavior of the asymmetric F-P cavity,the surface reflection color of the top layer Au film can be extended from the traditional yellow to the blue wavelength range,which,to some extent,breaks the inter-band transition limitation of Au material.The broaden color of Au film that covers the whole visible region can be realized by adjusting the thickness of the dielectric layer SiO ₂,and the color of Au film can be controlled through the phase transition of GST and the resonance behavior of incident light.In addition,we deeply studied the optical response of the designed structure to the change of the key parameters,such as the changes of gamut before and after the phase transition,the influence of incident angle and polarization on the reflective color,and the influence of GST layer and Au layer thickness on the reflective spectrum.Finally,we also reconstructed the generated color picture using the designed color filter.