Investigation on near-plane varied-line-spacing gratings made by electron beam lithography and near field holography
Final Report Abstract
Several constant line spaced and VLS‐gratings with different central line densities, e.g. 2400 lines/mm and 3600 lines/mm, have been realized. The fabrication involved EBL in VSB mode and subsequent mask transfer by dry etching technology. Significant for the overall scientific outcome was the implementation of a challenging variation in the line spacing. Within this research cooperation project a writing strategy for obtaining an increment as small as 0.1 nm has been established and successfully applied. In addition, advanced EBL methodology has been applied to all fabricated gratings to offer a high level of stitching accuracy. Thus on one hand, stray light peaks are several orders of magnitude lower compared to the efficiency of the designed grating diffraction orders and on the other hand, the overall amount of this undesired stray light is extremely low. The realization of chirped gratings with an increment of as small as 0.1 nm is technically extremely challenging and a concept as well as a proof of principle has been missing so far. Due to the concept principle the herein presented writing strategy is not restricted to a lower increment limit. Thus, and the fact, that an increment of 0.1 nm has been demonstrated successfully, are a unique incidence which are to be published soon.
Publications
- "Near‐field holography enhanced with antireflection coatings ‐ an improved method for fabricating diffraction gratings," Chin. Opt. Lett. 14, 090501 (2016)
Y. Li, H. Chen, S. Kroker, T. Käsebier, Z. Liu, K. Qiu, Y. Liu, E. Kley, X. Xu, Y. Hong and S. Fu
- Reducing Rowland ghosts in diffraction gratings by dynamic exposure near‐field holography, Opt. Lett. 43, 811‐814 (2018)
D. Lin, H. Chen, Z. Liu, K. Dietrich, S. Kroker, T. Käsebier, Y. Liu, E. Kley and Y. Hong
(See online at https://doi.org/10.1364/OL.43.000811)
