Minkevičius L, Indrišiūnas S, Šniaukas R, Voisiat B, Janonis V, Tamošiūnas V, Kašalynas I, Račiukaitis G, Valušis G
Opt Lett. 2017 May 15;42(10):1875-1878. doi: 10.1364/OL.42.001875.
Multilevel phase Fresnel lenses (MPFLs) with a high numerical aperture for 0.58 THz frequencies were developed. The components based on a monocrystalline silicon wafer are prepared by patterning by a high-speed industrial-scale laser direct writing (LDW) system. Two consistent series of the terahertz-MPFLs with phase quantization levels varying between 2 and the continuous kinoform shape for the focal lengths of 5 and 10 mm were produced employing inherent flexibility of the LDW fabrication process. The focusing performance was studied at the optimal 0.58 THz frequency using a Gaussian beam profile and scanning 2D intensity distribution with a terahertz detector along the optical axis. The efficiency of the terahertz-MPFL was found to be dependent of the number of subzones. The position and orientation angles of the patterned plane of the silicon wafer were considered to reduce the effect of standing waves formation in the experiment.
开发了用于0.58太赫兹频率的具有高数值孔径的多级相位菲涅耳透镜（MPFL）。基于单晶硅片的组件通过高速工业规模激光直写（LDW）系统进行图案化制备。利用LDW制造工艺的固有灵活性，制作了两系列一致的太赫兹-MPFL，其相位量化水平在2到连续的基诺夫形状之间变化，焦距分别为5毫米和10毫米。使用高斯光束轮廓并沿着光轴用太赫兹探测器扫描二维强度分布，在最佳0.58太赫兹频率下研究了聚焦性能。发现太赫兹-MPFL的效率取决于子区域的数量。在实验中考虑了硅片图案化平面的位置和取向角，以减少驻波形成的影响。
