On Friday October 22, 2021 at 13:15 in Lecture hall Rydberg Irene Geijselaers, Department of Physics, Solid State Physics, will publicly defend her doctoral thesis. Title: Optical studies of crystal phase heterostructures. Opponent appointed by the Faculty is Dr. Hannah Joyce, University of Cambridge, United Kingdom. Please, follow on Zoom: https://lu-se.zoom.us/j/62722309876?pwd=UEZHYlpJbFAwOU53VVNHTFgrN Passcode: 927587