Open AccessAbsorption enhancement of terahertz wave in microbolometers by titanium disk array
Author(s) -
Qingchen Niu,
Jun Gou,
Jun Wang,
Yadong Jiang
Publication year - 2019
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.68.20190902
Subject(s) - terahertz radiation , microbolometer , materials science , optoelectronics , absorption (acoustics) , optics , surface plasmon , resonance (particle physics) , plasmon , bolometer , detector , physics , composite material , particle physics
In this paper, a two-dimensional subwavelength periodic titanium (Ti) disk array integrated in micro-bridge structure is proposed to enhance the absorption of terahertz (THz) microbolometer. Based on the rigorous coupled wave analysis (RCWA) method, THz absorption characteristics of Ti disk arrays with different structure parameters in micro-bridge structure arrays are studied. Periodic disk array structure reduces the surface plasmon frequency of Ti, excites the spoof surface plasmons in the THz band and leads to resonance enhanced absorption. The resonance absorption frequency is determined by the structural parameters of Ti disk array including period and diameter while the absorption rate of THz wave is greatly affected by the thickness of Ti disks. The resonant cavity in micro-bridge structure can reduce the resonance frequency and enhance the coupling efficiency. The micro-bridge structure designed in this paper breaks the diffraction limit and traps the THz wave with a small period (37 μm). An absorption of nearly 90% is achieved at 3.5 THz. The structure meets the requirements of small size, high absorption and good process compatibility of the THz microbolometer.