New mechanisms of modulating optical properties
Contact: Prof. Yang Zhang
The past decades have witnessed unprecedented advances in the fields of optoelectronics and photonics. Despite such tremendous progress, new materials and novel phenomena continue to drive innovation. Yet much work remains to be done to attain a comprehensive understanding and control of novel materials as well as novel phenomena observed in them. Dynamic manipulation of optical properties in emerging materials through external fields (e.g., electric field, strain, etc.) has stimulated considerable scientific activities, for elucidating the fundamental physics and/or triggering technological applications. In recent years, there is an increasing awareness of exploiting smart materials in control of or coupling with various optical and optoelectronic materials. Smart materials have the ability to respond to external stimuli, such as electric or magnetic fields, strain, temperature and moisture, in a controlled manner. Piezoelectric and ferroelectric materials occupy an important position among the family of smart materials. Piezoelectric materials can produce electrical potential under mechanical stress. Conversely, they also response to applied electric fields with mechanical displacements. Ferroelectrics are a special class of piezoelectric materials, which have a spontaneous electric polarization that can be switched by an applied electric field. Piezoelectric and ferroelectric materials have shown enormous potential use for coupling with and control of electronic and optoelectronic properties of various materials, and have led to extremely fertile areas of research. There are three ways for ferroelectric and piezoelectric effects to impact on the optical processes in materials. They can act as external perturbations, such as ferroelectric gating and piezoelectric strain, to modulate the optical properties of various materials, particularly low-dimensional materials. Second, ferroelectricity and piezoelectricity as innate attributes have been found in some optoelectronic materials, which can couple with other functional features (e.g., semiconductor transport, photoexcitation, photovoltaics) in the materials giving rise to unprecedented device characteristics. The last way is artificially introducing optical functionalities into ferroelectric and piezoelectric materials, which provides an opportunity for investigating the intriguing interplay between the parameters (e.g., electric field, polarization, strain) and the introduced optical processes.
Our research focuses on controlling and modulating the optical properties of various materials and devices using ferroelectric and piezoelectric effects.
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