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EBAM technology is capable of making full-density, functional metallic components for numerous engineering applications; the technology is particularly advantageous in the aerospace, automotive, and biomedical industries where high-value, low-volume, custom-design productions are required. A key challenge in EBAM is overcoming deformation of overhangs that are the result of severe thermal gradients generated by the poor thermal conductivity of metallic powders used in the fabrication process. Conventional support structures (Figure 1a) address the deformation challenge; however, they are bonded to the component and need to be removed in post- processing using a mechanical tool. This process is laborious, time consuming, and degrades the surface quality of the product. The invented support design (Figure 1b) fabricates a support underneath an overhang by building the support up from the build plate and placing a support surface underneath an overhang with a certain gap (no contact with overhang). The technology deposits one or more layers of un-melted metallic powder in an elongate gap between an upper horizontal surface of the support structure and a lower surface of the overhang geometry. The support structure acts as a heat sink to enhance heat transfer and reduce the temperature and thermal gradients. Because the support structure is not connected to the part, the support structure can be removed freely without any post-processing step. Future work will compare experimental data with simulation results in order to validate process models as well as to study process parameter effects on the thermal characteristics of the EBAM process.

The new fabrication method is an electron lithography scheme enabling monolithic integration of multiple photonic devices on a single PIC. The technology was demonstrated by integrating both a widely-tunable distributed Bragg reflector (DBR) and distributed feedback (DFB) lasers on the same substrate. By controlling the central gap width and etch depth along the laser mirror length (shown in the figure below) the reflectivities can be tuned and the desired laser characteristics can be achieved without additional lithography cycles. Initially demonstrated on an indium phosphide substrate with DBR and DFB elements, the platform technology shows promise for various other materials and devices like III-V and II-VI semiconductors, silicon-on-insulator (SOI), and planar lightwave circuits (PLCs). With this versatility, the invention described here can streamline PIC production across diverse applications. Proof-of-concept results showcase the lithographic technique’s ability to produce high-performance photonic devices with side-mode suppression ratios over 50 dB (figure on the right) and output powers exceeding 5 mW. These metrics, combined with the lithographic simplicity, highlight the technology’s potential to reduce costs and accelerate PIC manufacturing. Please note that NASA does not manufacture products itself for commercial scale.