Research
Revolutionary properties of quantum materials are often manifestations of coherence and entanglement, e.g. it exists between the Cooper pairs in high-temperature superconductors (SCs); it protects chiral charge transport from disorder scattering in topological states of matter (TSM). The recent development of ultrafast spectroscopy and nano-imaging tools facilitates discovering and understanding driven coherent systems involving SCs, TSM and other quantum matter controllable by light. The history of modern scientific research is comprised of cycles of great discovery enabled by revolutionary new apparatus that allow for the study of new states of energy and matter. Currently, the challenge of pushing the switching speed-limit and integration density of today's logic and memory devices into the terahertz (THz, 1012 hertz) and sub-20 nanometer regime underlies the entire field of information processing, recording, storage and communication. Our central vision is to lead a paradigm shift towards "out-of-equilibrium" quantum approach for fundamental emergent materials discovery and nanoscale switching technology by engaging an all-optical quantum control strategy with various laser-induced, coherent excitations. We approach this via developing new ultrafast spectroscopy and more recently microscopy techniques with the simultaneous space, energy and time visualization under extreme conditions. These reveal hidden and unexpected details of quantum systems and hints about their control at their extreme, but salient scales: nanometer in space, femtosecond in time and milli-electron volts in energy.
Our current primary research projects are listed below. Please refer to the publication page and links below for our recent results.
1. Driven quantum systems and coherent control
2. Spectroscopy of emergent matter
3. Fundamental photovoltaic physics
4. Ultrafast nano-imaging/spectroscopy
5. Quantum femtosecond magnetism