Achromatic Quarter-Waveplate for the Terahertz Frequency Range Made by 3D Printing

Here we propose a 3D printed form-birefringent achromatic quarter-waveplate targeting the lower terahertz frequency range. The monolithically fabricated waveplate consists of three individual layers of different thickness and orientation of the stratified structure resulting in the achromatic response. The experimental results show that the performance of the fabricated waveplate fits the optimal behaviour within 5 % in terms of ellipticity and phase shift for frequencies between 75 GHz and 110 GHz.