Optimal de-excitation patterns for RESOLFT microscopy [Elektronische Ressource] / presented by Jan Keller

DissertationsubmittedtotheCombinedFacultiesfortheNaturalSciencesandforMathematicsoftheRuperto CarolaUniversityofHeidelberg,GermanyforthedegreeofDoctorofNaturalSciencespresentedbyDiplom PhysikerJanKellerborninLeipzigOralexamination: October18th,2006Optimalde excitationpatternsforRESOLFT MicroscopyReferees: Prof. Dr. StefanW.HellProf. Dr. JosefBilleAbstractRESOLFTmicroscopy hasbeenthe firstmethodthat iscapableof non invasivelyresolvingthreedimensionalstructureswithrealsubdiffractionresolutionusingvisiblelight. Itexploitsthe strong nonlinear saturation of a reversible optical transition. A focal intensity pattern isessential that de excites or de activates dyes outside the remaining ultrasharp effective fo cal spot. For a given amount of available power, the steepest applied de excitation patternwill yield the highest resolution. In this thesis, for the first time, a comprehensive search,optimization and characterization of de excitation patterns is performed. The microscope’spupil function is decomposed into orthonormal polynomials which allows the restriction ofthe space of pupil functions so that boundary conditions are fulfilled. The chosen globaloptimization algorithm converges reasonably well to pupil functions that can be idealizedfurthertosimpleshapes. Optimalpupilfunctionsarefoundaccordingtoassumptionsmadeabout the practical limitations. The optimization identified a novel, superior de excitationpattern for circularly polarized light.