Generation of a terahertz collimated top-hat beam by using two thin diffractive phase plates

Abstract

We propose an efficient approach for shaping a terahertz (THz) Gaussian beam to a collimated top-hat beam by using two thin diffractive phase plates. The phase plates are designed based on the phase retrieve algorithm and fabricated by well-developed 3D-printing technology. The designed THz top-hat beam is experimentally realized at 0.3-THz. Both the calculated root mean square (RMS) uniformity and fraction of the total beam power of the output top-hat beam are over 80%, respectively. Additionally, the comparison between our approach and the traditional system containing of two refractive aspheric lenses is performed. showing that our beam shaping system has higher energy utilization. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement