Nanoscribe, a specialist in micrometer 3D printing, has fabricated multi-level diffractive optical elements (DOEs) using its recently released Photonic Professional GT2 3D printer. The 3D printed microstructures will be presented at the upcoming Photonics West trade show for optics and photonics.
Multi-level DOE microstructures are becoming increasingly sought after in scientific research and certain industrial sectors. The tiny but complex devices can be used for a range of uses, including optical measuring, material processing and in security labels. Traditionally, however, multi-level DOEs are produced using planar lithography, which requires multiple steps.
Now, however, Nanoscribe has demonstrated how its own Photonic Professional GT2 3D printer can be be used to produce functional DOE prototypes and polymer masters for mass replication in a more cost-effective and streamlined way. Moreover, the high-resolution fabrication method enables the printing of submicron features and highly complex relief patterns.
DOEs themselves allow for the modification of lasers. In more specific terms, when a laser is shone through the device’s microstructure pattern, it can be transformed into any wanted intensity shape in the far field. By modifying the microstructure designs of the multi-level DOE, output can be customized.
Using the Photonic Professional GT2, Nanoscribe has shown how multi-level DOEs with details as small as a few hundreds of nanometers can be produced in a single printing step. The printer uses a two-photon polymerization process which emits a laser into a photoresin material, curing the material in a very precise manner. The laser focus scans the photoresin layer by layer, building up the tiny structure. When the printed part is complete, it is treated in a developing bath to remove any unpolymerized resin.
To support the printing capability of multi-level DOEs, Nanoscribe offers a workflow that encompasses a DOE import tool, a software tool for print preparation as well as the printer. The software is capable of processing high resolution DOE designs in a similar way to how STL files are imported for 3D printing.
As the company explains: “A phase distribution image of the DOE, computed by an external program, is imported directly by the printer software. Thus, the software calculates a height profile from the phase distribution. With the DOE software recipe the 3D printer transforms the DOE design in an optimized microrelief pattern.”
Nanoscribe’s Photonic Professional GT2 3D printer, launched in December, can be used to rapidly produce multi-level DOE prototypes as well as polymer masters which can then be used for mass replication. The technology will be showcased at Photonics West in San Francisco from February 2 to 5, 2019.