Open AccessDesign Method of Tunable Pixel with Phase‐Change Material for Diffractive Optical Elements
Author(s) -
Lee SeungYeol,
Kim Han Na,
Kim Yong Hae,
Kim TaeYoub,
Cho SeongMok,
Kang Han Byeol,
Hwang ChiSun
Publication year - 2017
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.17.0116.0004
Subject(s) - materials science , diffraction , dielectric , optics , stack (abstract data type) , wavelength , optoelectronics , broadband , pixel , diffraction efficiency , thin film , reflection (computer programming) , phase (matter) , computer science , physics , nanotechnology , quantum mechanics , programming language
In this paper, we propose a scheme for designing a tunable pixel layer based on a Ge 2 Sb 2 Te 5 (GST) alloy thin film. We show that the phase change of GST can significantly affect the reflection characteristic when the GST film is embedded into a dielectric encapsulation layer. We investigate the appropriate positions of the GST film within the dielectric layer for high diffraction efficiency, and we prove that they are antinodes of Fabry–Perot resonance inside the dielectric layer. Using the proposed scheme, we can increase the diffraction efficiency by about ten times compared to a bare GST film pixel, and 80 times for the first‐to‐zeroth‐order diffraction power ratio. We show that the proposed scheme can be designed alternatively for a broadband or wavelength‐selective type by tuning the dielectric thickness, and we discuss a multi‐phase example with a double‐stack structure.