Reflecting on space and time

This is a scientific autobiography. Starting as a postdoctoral fellow in physical chemistry at the Institute for Molecular Science in Okazaki, Japan, I learned elements of ultrafast spectroscopy, which I later applied at the Hitachi Advanced Research Laboratory. There, I started a research program on ultrafast surface photoelectron spectroscopy to measure hot electron relaxation rates, electronic coherence in nonlinear photoelectron spectroscopy of metal surfaces, and surface femtochemistry. I spent a total of 15 yr as a developing researcher in Japan and greatly benefited from the opportunities given to me, and I reciprocated by developing a new field of research. Eventually, however, I moved to the University of Pittsburgh as a full professor, where I expanded on what I initiated in Japan. This scientific journey was never envisioned as a plan; it evolved as I remained open to scientific discovery, which provided opportunities to learn along the way. A constant theme has been that I developed unique experimental capabilities that enabled me to pursue my own discoveries rather than to follow popular, well-trodden trends. Herein, I chart my progress, highlight the main accomplishments, note the contributions that were essential, and provide insights into ultrafast electronic phenomena in solid-state materials.