Public defence in Engineering Physics, M.Sc. Elena Ilina

Title of the doctoral thesis: Interferometric methods for aberration-insensitive imaging and generation of light beams with controlled group velocity

Opponent: Assistant Professor Marc Guillon, University of Paris, France
Custos: Professor Emeritus Matti Kaivola, Aalto University School of Science, Department of Applied Physics

The doctoral thesis is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic thesis

Public defence announcement:

Optical interferometry has many important applications in science and technology, including interferometric imaging systems, detectors, and sensors. The main goal of the research presented in this thesis is to utilize the interference effects for developing novel optical imaging methods and creating structured optical beams with controlled group velocity in free space.

The existing optical imaging systems that are used for non-invasive scanning of three-dimensional objects and imaging through turbid media are often not robust and have a relatively low resolution. An interferometric imaging method introduced in this work exhibits a high transverse resolution and is able to reveal sharp images even if the aberrations completely destroy the image. The method can significantly improve optical microscopy, endoscopy, and three-dimensional imaging systems.

The thesis also describes a method to create multifrequency Bessel beams with controlled group velocity in free space. It has been shown that by adjusting the propagation angle of the beam's plane-wave components, essentially arbitrary values of the group velocity can be achieved. An interferometric method has been proposed for measuring the group velocity of structured beams. Using this method, superluminal, subluminal, and negative group velocities with a magnitude several times higher than the speed of light in vacuum have been demonstrated. Such optical beams can find applications in intensity interferometry, ultrafast optics, optical tweezers, and nonlinear optics.

Contact details of the doctoral student: [email protected]