Microlenses have previously been created using microscopic glass blowing, but this typically entails gas expansion from a single reservoir. Researchers have now created a technique for fabricating axicons that use gas expansion from various reservoirs to create the conical shape of the optical component. Unlike conventional methods like etching transfer from a 3-D mask that engrave the wafer from above, the process shapes the surface from below, leaving a high-quality optical surface.
The researchers created concentric circles of glass that were sealed with silicon cavities to create the novel microscopic glass blowing technique. Gas that was confined in the cavities of the silicon and glass stack expanded when it was placed in a furnace, forming bubbles that had the shape of rings. These bubbles caused the glass surface to bulge into cone forms, then polished away to reveal the shaped lenses alone.
The procedures the researchers employed were all common for microfabrication, but they were used in novel ways to create tiny glass axicons. Other forms could be made using the method, even ones without cylindrical symmetry.
The scientists created a technique for fabricating axicons that combines gas expansion from various reservoirs to create the conical form of the optical component. Unlike conventional methods like etching transfer from a 3-D mask that engrave the wafer from above, the process shapes the surface from below, leaving a high-quality optical surface.
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