Laser fabrication of high efficiency focusing diffractive optics for the THz range

In this work transmission and reflection losses in silicon diffractive THz optical components fabricated by direct laser ablation are investigated. One of the possible sources of reflection/transmission losses in laser-fabricated optics is scattering due to the roughness of laser formed surface. Therefore, influence of laser processing parameters on the transmittance of laser processed silicon wafers was investigated in 0.1 –4.7 THz range. Transmittances of silicon samples ablated in ambient air and argon atmospheres were also compared. Using laser ablation technology MPFLs for 0.6 and 4.7 THz frequency radiation were fabricated and their performance was evaluated.