CC BY 4.0 UnportedAftenieva, OlhaSudzius, MarkasPrudnikau, AnatolAdnan, MohammadSarkar, SwagatoLesnyak, VladimirLeo, KarlFery, AndreasKönig, Tobias A.F.2023-02-222023-02-222023https://oa.tib.eu/renate/handle/123456789/11472http://dx.doi.org/10.34657/10505Miniaturized laser sources with low threshold power are required for integrated photonic devices. Photostable core/shell nanocrystals are well suited as gain material and their laser properties can be exploited by direct patterning as distributed feedback (DFB) lasers. Here, the 2nd-order DFB resonators tuned to the photoluminescence wavelength of the QDs are used. Soft lithography based on template-assisted colloidal self-assembly enables pattern resolution in the subwavelength range. Combined with the directional Langmuir–Blodgett arrangement, control of the waveguide layer thickness is further achieved. It is shown that a lasing threshold of 5.5 mJ cm−2 is reached by a direct printing method, which can be further reduced by a factor of ten (0.6 mJ cm−2) at an optimal waveguide thickness. Moreover, it is discussed how one can adjust the DFB geometries to any working wavelength. This colloidal approach offers prospects for applications in bioimaging, biomedical sensing, anti-counterfeiting, or displays.enghttps://creativecommons.org/licenses/by/4.0530620670confinement self-assemblydistributed feedback laserquantum dotssoft lithographyArticle