Open AccessMetal-insulator-metal strip spectroscopic infrared photothermal absorber based on uniaxially oriented plasmonic lanthanum hexaboride films
Author(s) -
Toan Phuoc Tran,
Thien Duc Ngo,
Hai Dang Ngo,
Sele Ørjan Handegård,
Tadaaki Nagao
Publication year - 2022
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.463522
Subject(s) - materials science , optoelectronics , fabrication , infrared , plasmon , lithography , optics , thin film , surface plasmon , nanotechnology , medicine , alternative medicine , physics , pathology
We report the fabrication of a mid-infrared device using LaB 6 - Al 2 O 3 - LaB 6 trilayers, with an array of LaB 6 strips as the top layer. Uniaxially oriented lanthanum hexaboride (LaB 6 ) films self-organized in a (100) orientation were adopted together with a lithographic process using laser direct writing followed by reactive ion etching. The fabricated infrared absorbers based on our electromagnetic design exhibited excellent resonant absorption and flexible tunability by changing the periodicity and width of the top LaB 6 strips. We examined the performance of epitaxial and sputtered LaB 6 films by fabricating two different types of absorbers using sputtered LaB 6 (100) and epitaxial LaB 6 (100) films for the bottom mirror layers. Owing to a difference in crystallinity, the latter exhibited a lower background in the absorption spectra as well as in the thermal emission spectra, indicating its good spectral selectivity.