Luminescence of PbS quantum dots spread on the core surface of a silica microstructured optical fiber

The broadband luminescence spectra, in the region from around 1000 to 1650 nm, of lead sulphide (PbS) quantum dots (QDs) spread onto the dual core surfaces of silica microstructured optical fibers (MOFs) (core diameters of ∼ 2.5 and ∼ 5.0 µm) are reported. For this purpose, colloidal solutions of PbS QDs of different sizes with luminescence bands around 877 (PbS877), 1160 (PbS1160), and 1474 nm (PbS1474) were injected and then spread onto the dual core surfaces of silica MOFs using a nitrogen gas pressure system. The PbS QDs were excited (via evanescent field effect) by the light of a continuum wave semiconductor laser or a Ti:sapphire laser (at 785 nm) guided through the MOF cores. As an important result, blue-shift and the band broadening behaviors in the luminescence spectra of these PbS QDs were observed.