Optical Properties Control of Hollow Core Microstructured Optical Fibers by Layer-by-Layer Assembled Quantum Dots and Annealing

Hollow core microstructured optical fibers (HC-MOFs) have attracted considerable attention in photonics, particularly for their potential in sensing applications in biology and medicine. This work presents a novel approach to modifying HC-MOF inner walls using quantum dots (QDs) and HC-MOF facets via hybrid membranes. These modifications are achieved through layer-by-layer (LbL) assembly, resulting in a reduced light transmission and a spectral red shift. Subsequent annealing restores transmission and induces a spectral blue shift. A similar effect is observed under low-pressure annealing when a mirror is installed on the facet of the modified fibers. An optimal method is demonstrated for these modifications and their impact is analyzed on HC-MOF transmission spectra and QDs photoluminescence. These findings highlight the practical approach to these modifications, paving the way for advanced HC-MOF-based sensors and multimodal probes in biomedical applications.