Final Report Summary - BIOLAS (Development of Novel Biological Lasers based on Fluorescent Proteins, Live Cells, and Self-Assembled Resonators) Biological structures with optical functionality have fascinated mankind for generations. Their application for bioinspired and bioderived optical devices might enable new photonic tools. An example of such a novel biooptical component is the biolaser that was developed by the Fellow. In this type of laser, coherent emission is generated e.g. by a single biological cell that is genetically programmed to produce a fluorescent material (the so called green fluorescent protein, GFP). During the integration grant, the fellow has worked on developing a better understanding of lasing and stimulated emission in biological materials and systems, improving the performance of biolasers, and developing new applications. The focus was initially on investigating biologically derived gain media, in particular different fluorescent proteins, and their in vitro characteristics as laser materials. Moreover, in vivo lasing based on cells expressing fluorescent proteins was studied in detail. Suitable resonators for completely natural lasers, in particular self-assembled structures, were investigated. While several other groups, including outside Europe, have become strong competitors over the past years, the integration grant has helped to maintain and cement the fellow competitive edge in the field. Synergies between work on organic lasers, intensively studied at the Fellow’s host institution, and the recently invented biolasers have rendered integration at the chosen host institution particularly successful.