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Analysis on Design and Fabrication of High-diffraction-efficiency Multilayer Dielectric Gratings

Authors :
Cho, Hyun-Ju
Lee, Kwang-Hyun
Kim, Sang-In
Lee, Jung-Hwan
Kim, Hyun-Tae
Kim, Won-Sik
Kim, Dong Hwan
Lee, Yong-Soo
Kim, Seoyoung
Kim, Tae Young
Hwangbo, Chang Kwon
Source :
Current Optics and Photonics; April 2018, Vol. 2 Issue: 2 p125-133, 9p
Publication Year :
2018

Abstract

We report an in-depth analysis of the design and fabrication of multilayer dielectric (MLD) diffraction gratings for spectral beam combining at a wavelength of 1055 nm. The design involves a near-Littrow grating and a modal analysis for high diffraction efficiency. A range of wavelengths, grating periods, and angles of incidence were examined for the near-Littrow grating, for the 0^th and –1^st diffraction orders only. A modal method was then used to investigate the effect of the duty cycle on the effective indices of the grating modes, and the depth of the grating was determined for only the –1^st-order diffraction. The design parameters of the grating and the matching layer thickness between grating and MLD reflector were refined for high diffraction efficiency, using the finite-difference time-domain (FDTD) method. A high reflector was deposited by electron-beam evaporation, and a grating structure was fabricated by photolithography and reactive-ion etching. The diffraction efficiency and laser-induced damage threshold of the fabricated MLD diffraction gratings were measured, and the diffraction efficiency was compared with the design’s value.

Details

Language :
English
ISSN :
25087266 and 25087274
Volume :
2
Issue :
2
Database :
Supplemental Index
Journal :
Current Optics and Photonics
Publication Type :
Periodical
Accession number :
ejs45499753