Investigation and optimization of Rowland ghosts in high efficiency spectrometer gratings fabricated by e-beam lithography

Martin Heusinger; Michael Banasch; Thomas Flügel-Paul; Uwe D. Zeitner

doi:10.1117/12.2211000

14 March 2016 Investigation and optimization of Rowland ghosts in high efficiency spectrometer gratings fabricated by e-beam lithography

Martin Heusinger, Michael Banasch, Thomas Flügel-Paul, Uwe D. Zeitner

Author Affiliations +

Proceedings Volume 9759, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics IX; 97590A (2016) https://doi.org/10.1117/12.2211000
Event: SPIE OPTO, 2016, San Francisco, California, United States

Abstract

Any violation of the periodicity of a perfect grating will result in diffuse scattering. In the particular case of a periodic violation the generated stray light shows deterministic, also periodic features that arise as distinct peaks in the stray light spectra, especially so-called Rowland ghosts. In this paper the characteristics of the spurious Rowland ghosts in binary spectrometer gratings are investigated and the potential of a randomization technique in order to suppress the Rowland ghosts is analyzed. Especially in sequential fabrication technologies, e.g. electron beam lithography, the Rowland ghosts originate in a segmentation process that is necessary in order to write large scale gratings. Hence several subareas are subsequentially exposed and stitched together leading to the final full size grating. Due to this stitching approach the subareas induce secondary periodic structures and thus generate the spurious Rowland ghosts in the order of magnitude of <10^-4 compared to the useful diffraction order. A randomization of this segmentation process is investigated both theoretically in rigorous simulations and experimentally by fabricating a purposely designed optical grating. As approach for the randomization in experiment we applied a special multi-pass-exposure. Here the sample is exposed multiple times with an accordingly shifted and dose-reduced subarea in each pass. The achieved simulation results show that a randomization of the subareas effectively reduces the Rowland ghosts. Furthermore the applied randomization technique during grating fabrication was able to suppress one kind of Rowland ghosts completely.

Citation Download Citation

Martin Heusinger, Michael Banasch, Thomas Flügel-Paul, and Uwe D. Zeitner "Investigation and optimization of Rowland ghosts in high efficiency spectrometer gratings fabricated by e-beam lithography", Proc. SPIE 9759, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics IX, 97590A (14 March 2016); https://doi.org/10.1117/12.2211000

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available