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Updated: Jun 24, 2026

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles
Published on: March 6, 2016
Design of a complex filter for depth of focus extension
Frédéric Diaz1, François Goudail, Brigitte Loiseaux
1Thales Research & Technology, RD 128, 91767 Palaiseau Cedex, France. frederic.diaz@thalesgroup.com
Abstract:
Different methods such as axilens and binary-phase filter have been investigated to improve the depth of focus. A method is proposed to calculate an amplitude-phase pupil filter and obtain the desired distribution of intensity along the optical axis. It produces a narrow spot with a uniform intensity level over a large depth of focus, comparable to the performance obtainable with binary-phase filters. This filter is of particular interest for applications where very low intensity fluctuations along the focus range are required.
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