Liebert, K., M. Rachoń, J. Bomba, A. Sobczyk, P. Zagrajek, M. Sypek, J. Suszek, and A. Siemion. “THz Diffractive Focusing Structures for Broadband Application”. Photonics Letters of Poland, vol. 10, no. 3, Oct. 2018, pp. 76-78, doi:10.4302/plp.v10i3.845.