Laser interference Photocuring: Fabrication of transmission diffraction gratings by one-step method

To face the challenges of expensive photoresist and complex process flow for fabricating diffraction grating structures, we propose an additive manufacturing (AM) strategy to obtain transmissive diffraction grating structures by laser interference photocuring (LIP). In this paper, the transmission diffraction gratings with a period of 7.5 μm is designed, and SEM images showed that the obtained period is about 7.40 μm ± 0.02 μm (the error approximately1.3 %). Furthermore, the energy dispersive X-ray spectroscopy (EDS) revealed that the carbon element is uniformly distributed on the structure of the transmission diffraction grating structures, and that the carbon element has a linear increasing trend with the increase of the LIP time. Eventually, the carbon element completely covered whole area after the LIP for 2 s. Moreover, these gratings also showed obviously diffractive performance, in which the efficiency was about 37 % at the zero-order, and it reach about 18 % at the first-order. Finally, a model was established to discuss the evolution of the grating structures. In conclusion, we have explored a new way to fabricate transmissive grating structures by LIP, which also provides new insights for scientists to achieve low-cost and high-efficiency fabrication of micro- and nanostructures on the surface of transparent substrates.