[2025] Magneto-acoustic 4D holograms

Reconfigurable acoustic systems have the potential to dramatically transform
wave manipulation in areas such as ultrasonic imaging, signal processing, and
acoustic metamaterials. This proposal introduces a novel strategy that uses
magnetic nanoparticles, patterned on a flexible elastomeric substrate via metal
current patterns, and placed atop a piezoelectric (PZT) transducer. Currently, the
primary way to shape acoustic wavefronts is through phased array transducers
(PATs), where each independently addressable transducer element can adjust its
phase and amplitude in real time. However, as pixel counts and information
content grow, the complexity and cost of PATs scale unfavourably due to the
extensive electronics needed for individual element control and synchronization.
To overcome these limitations, the project proposes a monolithic acoustic
hologram formed from electrically controllable magnetic particles on an
elastomeric substrate. Positioned in the path of a single ultrasonic transducer,
this hologram modifies the outgoing wave to produce a desired two-dimensional
phase profile. In doing so, it enables the creation of three-dimensional sound
fields with diffraction-limited resolution—yet relying only on a simple planar
transducer driven by a single function generator and amplifier [1], [2].
 

[1] K. Melde, A. G. Mark, T. Qiu, and P. Fischer, “Holograms for acoustics,” Nature,
vol. 537, no. 7621, pp. 518–522, Sep. 2016, doi: 10.1038/nature19755.
[2] Z. Ma et al., “Spatial ultrasound modulation by digitally controlling microbubble
arrays,” Nat Commun, vol. 11, no. 1, Dec. 2020, doi: 10.1038/s41467-020-18347-
2.

Assignment

1st part: Literature review on acoustic holograms and MATLAB simulation
(angular spectrum method) to develop various phase maps, COMSOL simulation
validation.
2nd part: Fabrication of acoustic holograms and integration on PZT transducer
and experimental testing to create various acoustic patterns

Requirements

MSc students from Microelectronics, Biomedical Engineering, Applied Physics or
Mechanical Engineering. Prior knowledge on COMSOL is preferred.
Interested students should include their CV, the list of courses attended, and a
motivation letter, and send it to Tiago Costa (t.m.l.dacosta@tudelft.nl) and
Eshani Sarkar (E.Sarkar@tudelft.nl)

Contact

Last modified: 2025-02-28