We present a powerful and efficient technique to structure acoustic fields, based on the use of active diffraction elements, which can be designed in practically arbitrary shapes and can be operated within a broad spectral range of ultrasonic frequencies in air. Two kinds of structured fields are demonstrated: focused acoustic vortices and the simultaneous generation of multiple acoustic Bessel beams of different topological charges, well separated among each other along the propagation axis. In both cases, the main parameters of the field can be finely and continuously tuned by setting the operation frequency. Experimental results show very good agreement with theoretical analysis and numerical simulations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.