Open AccessTunable THz notch filter with a single groove inside parallel-plate waveguides
Author(s) -
Eui Su Lee,
Tae-In Jeon
Publication year - 2012
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.20.029605
Subject(s) - terahertz radiation , band stop filter , groove (engineering) , optics , finite difference time domain method , materials science , transverse plane , sensitivity (control systems) , filter (signal processing) , waveguide , air gap (plumbing) , optoelectronics , physics , low pass filter , electronic engineering , structural engineering , computer science , metallurgy , composite material , computer vision , engineering
A single groove in a parallel-plate waveguide (PPWG) has been applied to a tunable terahertz (THz) notch filter with a transverse-electromagnetic (TEM) mode. When the air gap between the metal plates of the PPWG is controlled from 60 to 240 μm using a motor controlled translation stage or a piezo-actuator, the resonant frequency of the notch filter is changed from 1.75 up to 0.62 THz, respectively. Therefore, the measured tunable sensitivity of the notch filter increases to 6.28 GHz/μm. The measured resonant frequencies were found to be in good agreement with the calculation using an effective groove depth. Using a finite-difference time-domain (FDTD) simulation, we also demonstrate that the sensitivity of a THz microfluidic sensor can be increased via a small air gap, a narrow groove width, and a deep groove depth.