Nanoporous silicon multilayers for terahertz filtering.
We describe the fabrication, simulation, and measurement of a terahertz (THz) filter composed of nanoporous silicon multilayers. Using electrochemical etching, we fabricated a structure composed of alternating high- and low-index layers that achieves 93% power reflectivity at the target wavelength of 1.17 THz, with a stopband of 0.26 THz. The measured reflection and transmission spectra of the multilayer filter show excellent agreement with calculations based on the refractive indices determined separately from single-layer measurements. This technique could provide a convenient, flexible, and economical way to produce THz filters, which are essential in a variety of future applications.
Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA. alenciou@umd.edu
Shu-Zee A
SZ
Lo
Thomas E
TE
Murphy