Fabrication of hybrid freeform optical elements and structures

This thesis aims to utilise the unique characteristics of femtosecond direct laser writing (fs-DLW) technique to fabricate advanced 2D/3D micro- and nanophotonic devices. To achieve this objective, several micro- and nanophotonic devices developed with different fs-DLW fabrication techniques and approaches are proposed and demonstrated. This thesis is presented in terms of published original research papers with topical introductory descriptions and basic fundamentals, arranged in the research chapters.