Terahertz Wave Tunneling Through Subwavelength Rectangular Channel

Since the vibration and rotation spectrums of many biomolecules are in the terahertz band, the close relation between terahertz waves and many biological effects has been widely demonstrated. Whereas highly localized terahertz stimulation for subcellular study is challenging because the wavelength of terahertz waves is commonly much larger than the size of cells and molecules. Therefore we focus on the subwavelength wave tunneling effect in the terahertz band. The transmission-line model is investigated and then a specific wave tunneling waveguide aimed at 34THz is proposed. Finite element simulations are carried out for verification. The results show that the air-filled rectangular metallic tunneling waveguide can achieve a transmittance close to unity at the design wavelength with a bandwidth of about 0.06 THz. The transmittance is independent of the length of the tunneling channel, showing the ability to transmit confined terahertz waves over long distances.