Ultrafast Multilevel Optical Tuning with CSb₂Te₃ Thin Films

Abstract

Abstract Tunable and reconfigurable functionalities are crucial for advanced photonic devices. In this study, CSb 2 Te 3 is proposed as a new optical tuning material. Single‐shot picosecond laser pulses are used to transform the CSb 2 Te 3 into six different optical states; each optical state can be achieved from any other state. The dielectric function for each optical state is unique and the switching is achieved on a picosecond time scale. The impact of the crystal structure on the optical tuning mechanism is studied using transmission electron microscopy and density functional theory. Second harmonic generation in the CSb 2 Te 3 films indicates that the crystal orientation for the switched layer is influenced by the pump laser polarization. Thus electric field may provide a further degree of freedom to design phase change materials.