Frequency converting and digital modulation of light derived from lanthanide for signal encoding and logic computing

Modulation of light underpins a central part of modern optoelectronics.Con-ventional optical modulators based on refractive-index and absorption varia-tion in the presence of an electric field serve as the workhorse for diverse photonic technologies.However,these approaches based on electro-refraction or electro-absorption effect impose limitations on frequency converting and signal amplification.Lanthanide-activated phosphors offer a promising plat-form for nonlinear frequency conversion with an abundant spectrum.Here,we propose a novel approach to achieve frequency conversion and digital modula-tion of light signal by coupling lanthanide luminescence with an electrically responsive ferroelectric host.The technological benefits of such paradigm-shifting solution are highlighted by demonstrating a quasi-continuous and enhancement of the lanthanide luminescence.The ability to locally manipulate light emission can convert digital information signals into visible waveforms,and visualize electrical logic and arithmetic operations.The proof-of-concept device exhibits perspectives for developing light-compatible logic functions.These results pave the way to design more controllable lanthanide photonics with desired opto-electronic coupling.

Temperature-and thickness-dependence of robust out-of-plane ferroelectricity in CVD grown ultrathin van der Waals a-In2Se3 layers

Two-dimensional(2D)ferroelectric materials with unique structure and extraordinary optoelectrical properties have attracted intensive research in the field of nanoelectronic and optoelectronic devices,such as optical sensors,transistors,photovoltaics and non-volatile memory devices.However,the transition temperature of the reported ferroelectrics in 2D limit is generally low or slightly above room temperature,hampering their applications in high-temperature electronic devices.Here,we report the robust high-temperature ferroelectricity in 2D a-In2Se3,grown by chemical vapor depostion(CVD),exhibiting an out-of-plane spontaneous polarization reaching above 200℃.The polarization switching and ferroelectric domains are observed in In2Se;nanoflakes in a wide temperature range.The coercive field of the CVD grown ferroelectric layers ilustrates a room-temperature thickness dependency and increases drastically when the film thickness decreases;whereas there is no large variance in the coercive field at dfterent termperature from the samples with identical thickness.The results show the stable ferroelectricit of In2Se3 nanoflakes maintained at high temperature and open up the opportunities of 2D materials for novel applications in high-temperature nanoelectronic devices.