Metal mesh resonant filters for terahertz frequencies

Abstract

The interest in terahertz photometric and imaging measurements has motivated the development of bandpass resonant filters to be coupled to multiple-pixel devices such as bolometer arrays. Resonant grids are relatively simple to fabricate, exhibiting high transmission at the central frequency, a narrow bandpass, and good rejection of the side frequencies of the spectrum. We have fabricated filters centered at different frequencies between 0.4 and 10 THz, using photolithography and electroforming techniques. Transmission measurements have shown center frequencies and bandwidths close to the design predictions. The performance of the filters was found not to be critically dependent on small physical deformations in the mesh, becoming more noticeable at higher frequencies (i.e., for smaller physical sizes). Wider bandwidths, needed to attain higher sensitivities in the continuum, were obtained by changing the design parameters for filters at 2 and 3 THz.

Compact micromachined infrared bandpass filters for planetary spectroscopy

“…The screens were robust and showed high peak transmittance between 70µm and 172µm in spectral wavelength. More recently, Melo et al [11] successfully fabricated suspended resonant nickel metal mesh filters for discrete central wavelengths ranging from 30µm to 750µm using standard photolithographic techniques and their measured transmission and bandwidths correlated well with the simulations from a 3D EM simulator.…”

Микроволновый Полосно-Пропускающий Фильтр На Диэлектрических Слоях С Металлическими Сетками

“…Интерес к таким конструкциям обусловлен возможностью создания на их основе частотно-селективных поверх-ностей, служащих полосно-пропускающими фильтрами в диапазонах от субмикронных до дециметровых длин волн [1][2][3][4]. Полосковые элементарные ячейки, из которых состоит периодическая 2D-структура, например металлические квадраты или ячейки металлической сетки, являются резонаторами [5].…”

Ultra-low cost THz short-range wireless link

“…For narrower fractional bandwidths of operation (e.g. between 10% and 30%), metal mesh resonant filters can also be employed, as demonstrated by a 14% fractional bandwidth filter at 10 THz, patterned by a 2-dimentional array of halfwavelength sized crosses (15 μm in size) [5]. At 40 THz, the half-wavelength size of 3.75 μm is very close to the 1 μm minimum feature size limit for low-cost shadow mask manufacturing.…”