Terahertz antiresonant reflecting hollow-core waveguides for sensing applications

A dielectric hollow-core tube utilized as a terahertz anti-resonant reflecting hollow-core waveguide (THz-ARRHW) sensor has been demonstrated to detect the minute variation of both refractive index and thickness in macromolecule layers, deposited on the tube wall, and to identify liquid vapors from the various core indices. The minimal quantity of macromolecule layers loaded on the tube wall of a polypropylene tube can be detected at 1.2picomole/mm(2) and 0.2%, corresponding to the variation of 2.9 mu m-thickness and 0.001-refractive-index. The sensing performance of a THz-ARRHW to detect core index variation for identifying volatile liquids is also realized at 0.0001g/cm(3)-vapor density.