2026-04-17T17:04:17Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1246692025-12-05T14:45:35Zcom_2072_1057col_2072_478821col_2072_478917

00925njm 22002777a 4500 dc Martínez-Herrero, Rosario author Maluenda Niubó, David author Juvells Prades, Ignacio author Carnicer González, Arturo author 2018-09-18T15:45:00Z 2018-09-18T15:45:00Z 2018-02-08 2018-09-18T15:45:00Z 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. Polarització (Llum) Difracció Feixos de làser Polarization (Light) Diffraction Laser beams Synthesis of light needles with tunable length and nearly constant irradiance