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Tunable THz notch filter with a single groove inside parallel-plate waveguides

2012; Optica Publishing Group; Volume: 20; Issue: 28 Linguagem: Inglês

10.1364/oe.20.029605

1094-4087

Eui Su Lee, Tae‐In Jeon,

Photonic Crystals and Applications

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.