RESUMEN
We report on the operation of a highly sensitive terahertz imaging system relying on a planar metallic plasmonic crystal as a terahertz surface plasmon resonant (THz-SPR) sensor. The terahertz imaging is based on the resonantly enhanced transmission phenomenon of a periodically perforated metal film. The detection sensitivity and the imaging contrast for small amounts of substance are considerably better than those of the conventional terahertz transmission imaging without a THz-SPR sensor. As a demonstration, a high contrast image of a fingerprint recorded on a thin film can be achieved by using this system.
RESUMEN
A surface-wave sensor based on the resonant transmission characteristics of metal hole arrays is demonstrated in the terahertz (THz) region. Since the frequency of the transmission peak of a metal hole array, which corresponds to the resonant frequency of the surface waves, is particularly sensitive to the refractive index in the vicinity of the metal surface, a very small change in the substances attached to the surface can be detected by monitoring the transmission spectrum. By attaching a layer of substance (thickness t < 5 microm) much thinner than the wavelength of the THz wave (lambda(THz) = 1 mm at 0.3 THz) to the surface of a metal hole array, we demonstrated that the existence of such a small amount of substance can be detected more easily than without the metal hole array. This demonstration of THz sensing with metal hole arrays indicates the possibility of realizing THz surface-wave sensors for biochemical molecules in the THz region.
