Micromachined Air-Lifted Pillar Arrays for Terahertz Devices

Micromachined air-lifted pillar arrays have been designed, fabricated, and characterized in the range of 1-3 THz. The pillar arrays consist of high-aspect-ratio epoxy structures defined by ultraviolet lithography followed by sputtered metallization. A Bruker 113v Fourier transform infrared spectrometer (FTIR) system has been used to characterize the fabricated air-lifted pillar arrays for both p-( E-field parallel to the plane of incidence) and s-( E-field perpendicular to the plane of incidence) polarized incident waves. Measurement results are verified using resonant frequency calculation and Floquet mode simulation. In the p -polarization measurement, the pillar arrays with a diameter of 5 μm, and heights of 28, 39, 54, and 60 μm show quarter wavelength resonant frequencies at 2.16, 1.81, 1.46, and 1.38 THz, respectively, as predicted. Since the air dielectric architecture has no dielectric loss, it would enable highly power efficient terahertz devices such as a monopole antenna, a frequency selective surface, and an electromagnetic absorber.