Grant: Research Tools and Instruments

I am requesting funds for replacing a failed ultrafast laser, which is critically needed for rescuing my core experimental research program. RESEARCH PROGRAM. My research group at UBC specializes in developing experimental methods to investigate ultrafast dynamics of quantum media. In the course of these studies, we have built a number of unique optical instruments (e.g. an ultrafast "optical centrifuge"). Recently, we started applying these instruments to quantum many-body systems with strong inter-particle interactions, specifically - to superfluid liquid helium. We discovered that laser pulses can excite "rotons" - exotic quasi-particles which describe synchronous collective motion of a group of He atoms. The interactions of these quasiparticles with one another are strong and occur on ultrashort (femto- and picosecond) time scales. These interactions are not well understood, despite their key role in the phenomenon of superfluidity. The goal of this research program is to investigate ultrafast quantum dynamics of quasi-particles in superfluids for better understanding of strongly-interacting quantum materials. NEED and URGENCY. Without the requested replacement of the failed femtosecond laser, the above-mentioned goal is unattainable. Owing to the failed laser, the experimental setup became inoperative, causing the new and promising research project, which represents an important part of my overall research program, to stall. Our construction and utilization of the optical centrifuge allowed us to work at the very forefront of quantum science. If the laser system is not revived, our ability to put this advanced laser technology to work in the study of superfluids (where it has never been used before!) will not materialize, and the opportunity to pioneer a new direction of research in Canada will be lost. The failure of the experimental system puts on hold a PhD project of one senior graduate student, and seriously affects the prospects of a new PhD student, hired in 2023 to take over and continue this research effort. Together with another senior RA, all personnel working on this system is supported by my Discovery grant, whose utilization will be critically undermined by the inoperative instrumentation. ADVANCEMENT of KNOWLEDGE and TRAINING. Despite the widespread use of superfluid helium, the largely macroscopic phenomenological theory of superfluidity does not answer such fundamental questions as "what is a roton?" or "can rotons be controlled with light?" By answering these questions, my research program aims to provide better understanding of the microscopic origins of superfluidity. From the technical perspective, a femtosecond laser, whose replacement is requested here, is one of the key elements in ultrafast laser technology. Familiarity with, and training on, this device provides my students with exceptional and marketable skills, which are hard to acquire anywhere else.