DURIP: DEVELOPMENT OF FEMTOSECOND OPTICAL SCATTERING MICROSCOPY TO IMAGE AND CONTROL ENERGY AND INFORMATION FLOW IN EXOTIC MATERIALS

Through the DURIP, we will develop femtosecond optical scattering microscopy (femtoSCAT), a new imaging approach that will track energy and information flow in two-dimensional atomic, superatomic and molecular materials with sub-10 nanometer and sub-10 femtosecond spatiotemporal resolution. femtoSCAT represents a scientifically major upgrade to previous stroboscopic scattering microscopes developed in our group by improving temporal resolution 5000-fold. This advance will enable fleeting light–matter interactions of high relevance to defense technologies to be directly imaged and controlled for the first time. We target three new research capabilities empowered by femtoSCAT's exceptional spatiotemporal resolution and its unique ability to distinguish between charge, exciton, spin and phonon excitations. (i) First direct imaging of exciton–polariton propagation in real space and time in self-assembled molecular materials. The materials we target form natural photonic cavities in which trapped light hybridizes with material excitations, enabling energy steering and conversion at light-like speeds. Defense applications include lightweight solar panels that exceed current thermodynamic efficiency limits for self-sustaining ground, air and space missions, and defense against directed energy weapons. (ii) Optical launching and high-throughput imaging of spin wave propagation and its interactions with electronic currents in two-dimensional magnets. femtoSCAT will rapidly screen new materials for their compatibility with high-density wave-based (quantum) computing architectures that will transform information science. Wave-based computers and simulators are key to achieving technological dominance in communication and cryptography. (iii) Imaging and manipulating electron–phonon interactions in superatom assemblies to achieve the first laser-based, coherent control of ultrafast energy flow over hundreds of microns. Achieving such active control will lead to material platforms whose optical and electronic properties can be switched in picoseconds for ultrafast in-field adaptability. This research will be synergistic with AFOSR project 'Artificial Atoms, Molecules, and Solids: Multiple Functions and Emergent Properties' at Columbia University (FA9550-18-1-0020). Finally, the development of femtoSCAT by graduate, postdoctoral and undergraduate students in the group will contribute to workforce preparation in state-of-the-art optical sciences, equipment diagnosis, and multi-dimensional data analysis, complementing the training they receive in materials chemistry and condensed matter physics.