Open AccessSubwavelength film sensing based on terahertz anti-resonant reflecting hollow waveguides
Author(s) -
Borwen You,
Ja Yu Lu,
Jia Hong Liou,
Chao Yu,
Hao Zai Chen,
Tze An Liu,
Jinlong Peng
Publication year - 2010
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.019353
Subject(s) - terahertz radiation , materials science , overlayer , optics , tube (container) , dielectric , refractive index , sensitivity (control systems) , terahertz spectroscopy and technology , optoelectronics , physics , composite material , electronic engineering , engineering , condensed matter physics
A simple dielectric hollow-tube has been experimentally demonstrated at terahertz range for bio-molecular layer sensing based on the anti-resonant reflecting wave-guidance mechanism. We experimentally study the dependence of thin-film detection sensitivity on the optical geometrical parameters of tubes, different thicknesses and tube wall refractive indices, and on different resonant frequencies. A polypropylene hollow-tube with optimized sensitivity of 0.003 mm/μm is used to sense a subwavelength-thick (λ/225) carboxypolymethylene molecular overlayer on the tube's inner surface, and the minimum detectable quantity of molecules could be down to 1.22 picomole/mm(2). A double-layered Fabry-Pérot model is proposed for calculating the overlayer thicknesses, which agrees well with the experimental results.