A compressed-sensing ultrafast transmission electron microscope for single-shot nanometer and picosecond imaging of irreversible structural dynamics in action

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Many irreversible transient structural phenomena reflect important mechanisms in materials. Direct imaging of these events in real time (i.e., the actual duration of the event's occurrence) promises breakthrough advances in many scientific fields and brings attractive practical merits. However, this goal is inherently challenging due to the non-repeatability of these events, their picosecond temporal changes with microsecond evolution, and their nanoscopic spatial scales. Thus far, the development of capable imaging instruments has not kept up. Among existing techniques, movie-mode dynamic transmission electron microscopy (MM-DTEM) has the most potential to accomplish this goal. However, it is currently limited by its nanosecond temporal resolution and shallow sequence depth. Hence, the development of new single-shot ultrafast electron imaging instruments is specifically called on for investigating these irreversible transient structural dynamics. In response, we request to purchase an automated control system via this RTI grant, to develop compressed-sensing ultrafast transmission electron microscopy (CUTEM). This novel imaging system will feature single-shot real-time imaging at nanometer spatial resolution, picosecond temporal resolution, and a microsecond recording window. CUTEM will be applied to imaging three irreversible events: laser-induced vaporization, phase transition of non-volatile memory materials, and self-assembly of nanoparticles. The requested equipment is perfectly suited and is indispensable to the proposed research. The proposed research has compelling scientific merits and far-reaching potential applications. Compared with the state-of-the-art MM-DTEM, CUTEM will enhance the temporal resolution by 1000 and the sequence depth by 100. CUTEM will also open new avenues for studying previously inaccessible physics and chemistry in materials. Fully complementary and synergistically integrated to the MM-DTEM machine (a CFI-funded infrastructure) at INRS, CUTEM will significantly enhance the overall research abilities of the PI, the collaborator, and users. Finally, the proposed research will generate precious strategic advantages over other competing groups worldwide and place Canada in a leading position in this highly competitive field. The excellent track records and complementary expertise of the PI and the collaborator will ensure fast progress and overall success of the proposed program as well as make the most efficient and diligent use of the requested equipment. The proposed program has also attracted 11 major users in diverse fields at national and international premier institutes. Beyond its scientific merits, these research activities will provide the best possible training environment to attract and retain highly qualified personnel (HQP) for obtaining highly marketable skills for their future careers. CUTEM will be a perfect platform to promote and reinforce equity, diversity, and inclusion in HQP training.