Skip to main content

Refine your search

Valo. Kuva Mostphotos.

Doctoral defence, Mengwen Guo, PhD, 30.8.2023: Polarization and electromagnetic coherence in three-dimensional light fields

The doctoral dissertation in the field of Physics will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus.

What is the topic of your doctoral research? Why is it important to study the topic?

The research focuses on the polarization and coherence properties of random three-dimensional light fields. Recently, an increasing attention has been paid to three-dimensional optical fields due to the rapid progress in nonparaxial optics and nanophotonics. However, these fields are more elusive than their two-dimensional counterparts on account of the mathematical complexity and the description of such fields requires extended theories of polarization and electromagnetic coherence. Furthermore, three-dimensional light fields exhibit intricate polarization structures whose physical understanding requires appropriate characterization beyond the common, yet not general, case of two-dimensional polarization states. The research contributes to the knowledge of fundamental properties of three-dimensional optical fields and fosters potential progress in optical science and technology.

What are the key findings or observations of your doctoral research?

1. Introduction of the mutual polarization correlation functions for the description of correlations between polarization-state fluctuations in random two-dimensional and three-dimensional fields.2. A novel method to measure the spatial coherence properties of three-dimensional light fields by using two dipolar nanoscatterers. 3. An efficient approach to analyze the polarization properties of three-dimensional fields produced in a general 2D to 3D transformation optical system.4. Assessment of the three-dimensional polarization features of an evanescent field created in a double-prism optical-tunneling system.

How can the results of your doctoral research be utilised in practice?

The findings provide new insights and approaches for studies on the polarization and electromagnetic coherence of three-dimensional light fields. The foundational research may find applications in optical communication, surface nanophotonics and scanning near-field optical microscopy.

What are the key research methods and materials used in your doctoral research?

The research includes theoretical studies involving analytical calculations and numerical methods.

The doctoral dissertation of Mengwen Guo, PhD, entitled Polarization and electromagnetic coherence in three-dimensional light fields will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will Professor Colin J. R. Sheppard, University of Wollongong, Australia, and the custos will be Professor Tero Setälä, University of Eastern Finland. Language of the public defence is English.