Terahertz near-field vectorial imaging of subwavelength apertures and aperture arrays.
We present measurements of the complete terahertz (THz) electric near-field distribution, E(x), E(y) and E(z), in both the time- and frequency-domains, for subwavelength apertures and subsections of subwavelength aperture arrays. Measuring the individual components of the THz near-field with subwavelength spatial resolution, as they emerge from these structures, illustrates how the field interacts with the apertures. We observe the small but measurable y- and z-components of the electric field for both single apertures and arrays. Resonant contributions, attributed to Bloch modes, are detected and we observe the presence of a longitudinal field component, E(z), within the different array apertures, which can be attributed to a diffractive effect. These measurements illustrate in detail the individual THz field components emerging from subwavelength apertures and provide a direct measure of two important mechanisms that contribute to the net transmission of light through arrays.
Knab
J R
JR
Delft University of Technology, Faculty of Applied Sciences, Department of Imaging Science and Technology, Optics Research Group, Lorentzweg 1, 2628 CJ Delft, The Netherlands. J.R.Knab@tudelft.nl
Adam
A J L
AJ
Nagel
M
M
Shaner
E
E
Seo
M A
MA
Kim
D S
DS
Planken
P C M
PC
D003198:Computer Simulation; D004867:Equipment Design / Q000379:methods; D008422:Materials Testing; D055095:Optics and Photonics; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D012825:Silicon / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods; D055068:Terahertz Spectroscopy / Q000379:methods*
D012825:Silicon