Development of an automated prototype of THz filter based on magnetic fluids

Abstract

We report on the fabrication of liquid automated filter capable of controlling the intensity of terahertz radiation in the range of 0.4-1.4 THz. The filter is a cell with a magnetic fluid (5% dispersion of 5BDSR particles in 80W-90 synthetic oil) placed on the path of THz radiation between a pair of crossed Helmholtz coils. The prototype created allows achieving an extremely high attenuation coefficient, up to 35 dB. Automatic start-up and stirring system make filter operation repeatable, even with multiple on/off filter state changes. All this allows us to speak about the operability of the presented technology and the possibility of further development of the prototype, the use of similar filters in any THz photonics systems, in which it is required to control the intensity of polarized radiation.