Terahertz refractive index sensors using dielectric pipe waveguides

Abstract

A dielectric pipe waveguide is successfully demonstrated as a terahertz refractive index sensor for powder and liquid-vapor sensing. Without additional engineered structures, a simple pipe waveguide can act as a terahertz resonator based on anti-resonant reflecting guidance, forming multiple resonant transmission-dips. Loading various powders in the ring-cladding or inserting different vapors into the hollow core of the pipe waveguide leads to a significant shift of resonant frequency, and the spectral shift is related to the refractive-index change. The proven detection limit of molecular density could be reduced to 1.6nano-mole/mm³ and the highest sensitivity is demonstrated at around 22.2GHz/refractive-index-unit (RIU), which is comparable to the best THz molecular sensor [Appl. Phys. Lett. 95, 171113 (2009)].

Terahertz Refractive Index Sensing Based on Photonic Column Array

“…A crucial limitation based on these planar geometries is incompatibility with dynamical online monitoring for liquid materials. Sensors based on waveguide structures such as metal parallelplate waveguide [9], [10], photonic crystal waveguide [11], or hollow pipe fiber [12] have strong resonances with high sensitivity and their geometry is comfortable for monitoring liquids. Take Ref.…”

Metal plate for guiding terahertz surface plasmon-polaritons and its sensing applications

“…Since they are first proposed, there are many similar THz waveguides [4][5][6][7] have been studied, and many interesting theoretical and experimental conclusions have been given. THz waveguides have been widely used in communications, spectroscopy, imaging, detection and sensing [8][9][10][11]. The sensing of the thin dielectric film on the cylindrical metal wires are reported by several articles [10,11].…”

THz wave in double-metal-film waveguides and the application of wavelength analysis

“…In recent years, requirements of THz function devices [1][2][3] are frequently in the THz field, so the developments of these devices are essential. There have been all sorts of THz waveguides [4][5][6], such as metal wire waveguides [7][8][9][10][11], dielectric pipe waveguides [12][13][14][15][16][17][18], parallel plate waveguides [19][20][21][22][23], anti-resonant reflecting hollow waveguides [24,25], single metal plate waveguides [26][27][28][29][30], THz fibers [3,31,32], and metal tubes [33]. Since they are proposed, many aspects of new physics and applications have been researched, and many interesting theoretical and experimental conclusions have been given.…”

“…Since they are proposed, many aspects of new physics and applications have been researched, and many interesting theoretical and experimental conclusions have been given. These waveguides are used for different functions, such as endoscope [7] and sensor applications of metal wire [10,11], dielectric pipe sensor [16,17], parallel plate sensor [22] and filter [23], single metal plate sensor [26][27][28][29][30], and THz switches [34,35]. These have promoted the THz field greatly.…”