Open dissemination of results through publications is the core element of “open science”. However, if important dimensions of knowledge are not accessible through access to publications alone, open science may not in fact be as effective in knowledge dissemination as the economics of science would have it. In this paper we explore the importance of knowledge transfer through face-to-face contacts and role model learning. Our approach emphasizes the directional nature of knowledge flows from senior to junior researchers. The study is based on a unique dataset encompassing more than 6,000 doctoral dissertations in German laser research over a period of close to 50 years, which we match with additional information about the publication and patenting activities of the respective researchers, as well as their future career tracks. In particular, we are able to identify whether or not an individual has ever attained a professorship at a German university. In the German educational system doctoral students traditionally work with a single individual advisor (the “Doktorvater”) who strongly shapes the direction of their research. We exploit this fact that to develop a genealogy of German laser research spanning several academic “generations.” Our data show that a substantial share of recent laser-related doctoral dissertations have a direct lineage to the first generation of German laser researchers. We also quantify the effect of being an offspring of a German laser pioneer on the average number of laser-related dissertations that an individual researcher subsequently advises him-/herself, and on the likelihood of attaining a professorship. In addition, we trace similarities in the number and kind of laser-related publications and patents between advisors and doctoral students, as well as among doctoral students who had the same advisor.