Dynamic complex opto-magnetic holography

• Published in: Nature communications Vol. 13; no. 1; pp. 7286 - 11
• Main Authors: Makowski, M, Bomba, J, Frej, A, Kolodziejczyk, M, Sypek, M, Shimobaba, T, Ito, T, Kirilyuk, A, Stupakiewicz, A
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 26.11.2022; Nature Publishing Group UK; Nature Portfolio
• Subjects: Algorithms; Computation; Computer applications; Computer memory; Femtosecond pulses; Fourier transforms; Holography; Image reconstruction; Magnetic recording; Optical switching; Spatial light modulators; Wave fronts
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-35023-9

Despite recent significant progress in real-time, large-area computer-generated holography, its memory requirements and computational loads will be hard to tackle for several decades to come with the current paradigm based on a priori calculations and bit-plane writing to a spatial light modulator. Here we experimentally demonstrate a holistic approach to serial computation and repeatable writing of computer-generated dynamic holograms without Fourier transform, using minimal amounts of computer memory. We use the ultrafast opto-magnetic recording of holographic patterns in a ferrimagnetic film with femtosecond laser pulses, driven by the on-the-fly hardware computation of a single holographic point. The intensity-threshold nature of the magnetic medium allows sub-diffraction-limited, point-by-point toggling of arbitrarily localized magnetic spots on the sample, according to the proposed circular detour-phase encoding, providing complex modulation and symmetrical suppression of upper diffractive orders and conjugated terms in holographically reconstructed 3-D images.