Nanofibers for photonics: photoactive networks and molecular photoswitches

Polymer nanofibers have gained increasing attention for their physical properties and potential applications in various fields. The variety of nanofiber network topologies and the ability to incorporate photoactive dopants in optically transparent polymers make hybrid nanofibers suitable for nanophotonics applications. Hybrid nanofibers offer photon guiding with low propagation losses and stable emission, making them ideal for studying light propagation and scattering in interconnected networks, crucial for random lasing studies. However, effective experimental techniques to control the assembly of nanofibers in 3D architectures are still lacking. Additionally, using nanofibers in sensing platforms requires control by external stimuli. This thesis develops fibers networks with nanoscale light sources and optical properties controllable by multiple light signals. Nanofibers were fabricated using electrospinning, which elongates a polymer solution with an electrostatic field. Electrospinning was combined with 3D printing to create structures with controlled 2D and 3D fiber alignment. Additionally, hybrid nanofibers with quantum dots were used to study multiple scattering effects. Thin films and electrospun fibers incorporating two photochromic molecules were also developed to create a multi-photoaddressable system, controlled by opto-thermal signals to manipulate optical properties like absorption and photo-induced birefringence.