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Projekt Druckansicht

Mikroaxicons für ultrakurze Wellenpakete III - MAXWELL III

Antragstellerinnen / Antragsteller Dr. Rüdiger Grunwald; Professorin Dr.-Ing. Ulrike Wallrabe
Fachliche Zuordnung Mikrosysteme
Messsysteme
Förderung Förderung von 2019 bis 2022
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 427422724
 
Erstellungsjahr 2022

Zusammenfassung der Projektergebnisse

In the joint DFG project, we developed novel types of low-dispersion and robust adaptive beam shaping components for ultrashortpulsed lasers. Because of the close interdisciplinary collaboration, technological aspects of design and fabrication could be studied in direct coupling to advanced experiments in ultrafast optics and structured light. In particular, the capability to fast and flexibly shape so-called “nondiffracting” wave packets which propagate with unchanged characteristics over extended distances was successfully demonstrated. Particular emphasis was laid on piezo- and thermally actuated axicons and components for the generation of orbital angular momentum beams with tunable topological charges. In the final phase, MAXWELL III, it was demonstrated that a combination of fast actuated mirrors with highspatial-resolution liquid-crystal-on-silicon spatial light modulators (SLM) allows to exploit their specific advantages and to realize systems with extended functionality. Specifically, diffraction can be minimized by adapted illumination in “self-apodization” mode where no light hits the edges of components. This enables for generating diffraction-less beams of optimal quality. The phenomenon of nondiffracting self-imaging which we previously described for the first time was extended to higher flexibility. By combining a SLM and piezo-actuated fluid lens, a fast manipulation of self-imaging was obtained. Moreover, the technological basis for adaptive arrays with variable pitch was developed. The concept promises a large application potential, e.g. in metrology, materials processing or biomedicine. Modified free-form Fresnel bi-mirrors for the generation of accelerating (Airy-like) beams were developed. Reflective operation enables to transform even extremely short pulses because of minimum dispersion. By flexibly encoding ultrafast sub-beams with spatially variable parameters, the performance of Shack-Hartmann wavefront sensors was improved. In experiments with programmable densely-packed arrays of Bessel beams, needle beams and orbital angular momentum beams (topological encoding) it was shown that individual sub-beams can be recognized even under extreme conditions like passing a steep refractive edge. The classical wavefront sensor concept is extended to higher reliability. New types of transmissive components were fabricated and their performance was characterized at short pulses. In combined systems, fluid lenses were used to modify spatio-temporal field structures and pulse propagation by fast modulating the divergence. The obtained progress in system design, fabrication technologies and application research provides a profound basis for next generation photonic devices. To highlight the most important findings: • Design, technology and test of actuated Optical MEMS (microaxicons, spiral phase plates, Fresnel mirrors) • Single structures and arrays, Fresnel bi-mirrors • Combined systems (SLM plus MEMS, SLM plus fluid lens), self-apodization • Extension of the nondiffracting self-imaging phenomenon towards tunability • Smart wavefront sensing with OAM encoded and nondiffracting sub-beams • Advanced Optical MEMS for flexible generation of accelerated beams (Airy-like beams).

Projektbezogene Publikationen (Auswahl)

 
 

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