摘要
In cutting-edge optical technologies,polarization is a key for encoding and transmitting vast information,highlighting the importance of selectively switching and modulating polarized light.Recently,anisotropic two-dimensional materials have emerged for ultrafast switching of polarization-multiplexed optical signals,but face challenges with low polarization ratios and limited spectral ranges.Here,we apply strain to quasi-one-dimensional layered ZrSe_(3)to enhance polarization selectivity and tune operational energies in ultrafast all-optical switching.Initially,transient absorption on unstrained ZrSe_(3)reveals a sub-picosecond switching response in polarization along a specific crystal axis,attributed to shifting-recovery dynamics of an anisotropic exciton.However,its polarization selectivity is weakened by a slow non-excitonic response in the perpendicular polarization.To overcome this limitation,we apply strain to ZrSe_(3)by bending its flexible substrate.The compressive strain spectrally decouples the excitonic and nonexcitonic components,doubling the polarization selectivity of the sub-picosecond switching and tripling it compared to that in the tensile-strained ZrSe_(3).It also effectively tunes the switching energy at a shift rate of~93 meV%-1.This strain-tunable switching is repeatable,reversible,and robustly maintains the sub-picosecond operation.First-principles calculations reveal that the strain control is enabled by momentum-and band-dependent modulations of the electronic band structure,causing opposite shifts in the excitonic and non-excitonic transitions.Our findings offer a novel approach for high-performance,wavelength-tunable,polarization-selective ultrafast optical switching.
基金
supported by the National Research Foundation of Korea(NRF)through the government of Korea(MSIP)(Grant NRF-2022R1C1C1003124)
funded by grants from the National Research Foundation of Korea(2022M3H9A2096197)
the Korea Basic Science Institute(A439200).
作者简介
Correspondence:Sangwan Sim,swsim@hanyang.ac.kr。
