Resolution in coherent and incoherent optical imaging with two–photon excitation microscopy

Abstract

Driven by both curiosity and applications in healthcare, biomedical sci-entists seek to understand the complex machinery that is the human body. As a biophysicist, I contribute to this quest by developing new lab techniques. Tissues, cells, cell organelles,... the small sizes of many biological structures explain the need for increasingly better–performing imaging systems. Because diffraction limits the resolution in conventional optical microscopes to several hundred nanometers, other methods are needed to study biological samples at the desired resolution. In this work, several possible ways to challenge the diffraction limit are presented. The thesis starts with two general chapters, the first being an introduction in microscopy, the second providing the necessary mathematics describing the image formation process. In the other chapters, of which three are based on original publications, several methods to circumvent the diffraction limit are described. Finally, a brief summary and an outlook are presented in the conclusion.