%0 Journal Article
%A Martínez Herrero, María Rosario
%A Maluenda, David
%A Carnicer, Artur
%T Synthesis of light needles with tunable length and nearly constant irradiance
%D 2018
%@ 2045-2322
%U https://hdl.handle.net/20.500.14352/11989
%X 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 53 lambda-long and 0.8 lambda-wide needle.
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