Martínez-Herrero Rosario, Maluenda David, Juvells Ignasi, Carnicer Artur
Departamento de Óptica, Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Ciudad Universitaria, 28040, Madrid, Spain.
Departament de Física Aplicada, Universitat de Barcelona (UB), Facultat de Física, Martí i Franquès 1, 08028, Barcelona, Spain.
Sci Rep. 2018 Feb 8;8(1):2657. doi: 10.1038/s41598-018-21007-7.
We introduce a new method for producing optical needles with tunable length and almost constant irradiance based on the evaluation of the on-axis power content of the light distribution at the focal area. According to theoretical considerations, we propose an adaptive modulating continuous function that presents a large derivative and a zero value jump at the entrance pupil of the focusing system. This distribution is displayed on liquid crystal devices using holographic techniques. In this way, a polarized input beam is shaped and subsequently focused using a high numerical aperture (NA) objective lens. As a result, needles with variable length and nearly constant irradiance are produced using conventional optics components. This procedure is experimentally demonstrated obtaining a 53λ-long and 0.8λ-wide needle.
我们基于对焦平面处光分布的轴上功率含量的评估，介绍一种用于制造长度可调且辐照度几乎恒定的光针的新方法。根据理论考量，我们提出一种自适应调制连续函数，该函数在聚焦系统的入瞳处具有大的导数和零值跃变。利用全息技术将这种分布显示在液晶器件上。通过这种方式，对偏振输入光束进行整形，随后使用高数值孔径（NA）物镜进行聚焦。结果，使用传统光学元件制造出了长度可变且辐照度近乎恒定的光针。通过实验证明了该过程，获得了一根长度为53λ且宽度为0.8λ的光针。
