Control of broadband optically generated ultrasound pulses using binary amplitude holograms.
In this work, the use of binary amplitude holography is investigated as a mechanism to focus broadband acoustic pulses generated by high peak-power pulsed lasers. Two algorithms are described for the calculation of the binary holograms; one using ray-tracing, and one using an optimization based on direct binary search. It is shown using numerical simulations that when a binary amplitude hologram is excited by a train of laser pulses at its design frequency, the acoustic field can be focused at a pre-determined distribution of points, including single and multiple focal points, and line and square foci. The numerical results are validated by acoustic field measurements from binary amplitude holograms, excited by a high peak-power laser.
Department of Medical Physics and Biomedical Engineering, University College London, 2-10 Stephenson Way, NW1 2HE London, United Kingdom.
Michael D
MD
Brown
Faculty of Information Technology, Brno University of Technology, Bozetechova 2, 612 66 Brno, Czech Republic.
Jiri
J
Jaros
Department of Medical Physics and Biomedical Engineering, University College London, 2-10 Stephenson Way, NW1 2HE London, United Kingdom.
Ben T
BT
Cox
Department of Medical Physics and Biomedical Engineering, University College London, 2-10 Stephenson Way, NW1 2HE London, United Kingdom.
Bradley E
BE
Treeby