Phase Array AODs

phase array AOD

In standard AODs, generally the ultrasonic waves are generated by a single transducer which provides a good performance but has got some limitations though, most particularly when used as a deflector. In such device, the transducer is optimized over a frequency ∆F around a central frequency Fc in order the output diffracted optical beam can be steered. Due to the unmatched Bragg conditions, the diffraction efficiency is not constant across the frequency range and this could be problematic in some applications.

Phased-array transducer AO cell

For a specific project, AA developed a Phase Array AODs, a phased-array transducer AO cell, in order to cope with the decrease in the diffraction efficiency when the frequency is at +/- ∆F. It consists of having step-sectional transducer to generate the acoustic bema with a rotation radiation pattern. The acoustic wavefront is rotated with the changing frequency in order to maintain an optimal bragg angle between the optical & acoustic beam.

Product highlights

  • Operating wavelength: 355 nm
  • Diffraction efficiency > 85%, nom 90% over whole bandwidth
  • Scan angle 4.5 mrad