DOI: 10.25442/hku.25532479
title: Supporting dataset for Additive Manufacturing of Micro Photon Sources

description: Microscale photon sources refers to devices or structures that enable generation and manipulation of photons (the fundamental particle of light) at the microscale , which enables diverse applications such as data communication, sensing and imaging, quantum technologies due to its outstanding miniaturization and integration capabilities. Their versatility and efficiency make them vital components in advanced photonic and electronic circuits.Fluorescence labels composed of luminescent materials can be regarded as photon sources because it can emit photons when excited by an external light source. Light emitting diode (LED) is also a good example of photon sources, which can generate photons by releasing the recombination energy when injected by electric current. However, when it comes to downsizing these devices or structures to microscale, individual pixel level, most of the developed method that relied on complicated, costly lithography would be inadequate in terms of resolution, materials choice, freeform shaping capability, etc.To solve the abovementioned issues, this thesis introduces the novel strategy on additive manufacturing of microscale photon sources by means of nano-ink printing techniques. The kernel idea is to exploit ultrasmall-volume inks in the form of a meniscus or a droplet formed by a printing nozzle with a micron-sized aperture. Assisted by programmable solvent engineering, our approach can fabricate micro-or nano luminescent architectures with diverse materials choices, as microscale photon sources demonstrating optical anticounterfeiting functionalities.First, we developed vertically stacked, luminescent heterojunction micropixels that construct high-resolution, multiplexed anticounterfeiting labels. This is enabled by meniscus-guided three-dimensional (3D) microprinting of red, green, and blue (RGB) dye-doped materials. High-precision vertical stacking of subpixel segments achieves full-color pixels without sacrificing lateral resolution, achieving a small pixel size of∼μm and a high density of over 13,000 pixels per inch. Furthermore, a full-scale color synthesis for individual pixels is developed by modulating the lengths of the RGB subpixels. Taking advantage of these unique 3D structural designs, trichannel multiplexed anticounterfeiting Quick Response codes are successfully demonstrated.Second, we developed a direct electrohydrodynamic 3D printing that produces freestanding inorganic perovskite sub-microlasers with tailored dimensions and locations. The printed nanowires exhibited vertically aligned feature polycrystalline nature and well-defined diameter and length by changing printing parameters and applying solvent engineering. The resulting structures successfully showed a two-photon pumped Fabry–Pérot mode lasing with excellent lasing performance (P<sub>th</sub>: 2.98 µJ/cm<sup>2</sup>, Q factor: 2700), which was thoroughly investigated, and our on-demand printing method provides the simplest route to tune the lasing characteristics such as lasing threshold and mode spacing to date, by adjusting the printed nanowire length. In this work, we utilized the length-dependent-lasing in the printed arrays to configure multi-level anticounterfeiting labels.Lastly, we expect these works can give inspiration and pave the flexible, cost-effective way for additive manufacturing of integrated photonic devices. Apart from the photoluminescence-induced demonstrations, they can be extended to microscale electroluminescent displays by integrating diverse materials, thanks to the flexibility and precision of the technique.