GHz acousto-optic angular momentum with tunable topological charge.

Area of Science:

• Acoustic and Optical Physics
• Nanotechnology
• Optomechanics

Background:

• Control over wave symmetry is crucial for optical and mechanical applications.
• Orbital angular momentum (OAM) offers a powerful tool for wave manipulation.
• Existing methods for generating OAM in acoustic waves are limited.

Purpose of the Study:

• To introduce a novel device for generating acoustic vortices.
• To demonstrate the device's capability to impart OAM modulation on light.
• To explore applications in light communication and particle manipulation.

Main Methods:

• Device fabrication through shape-engineering of a single-contact bulk acoustic wave resonator.
• Generation of acoustic vortices across a wide frequency band (around 4 GHz).
• Tunable topological charge of acoustic vortices (1 to beyond 13) via geometry and excitation frequency.

Main Results:

• Successful generation of acoustic vortices with tunable topological charges.
• Demonstration of OAM modulation on reflected light beams at super-high frequencies.
• Achieved wideband operation around 4 GHz.

Conclusions:

• The developed device provides an on-chip, all-electrical solution for acoustic vortex generation.
• Offers compact and tunable OAM modulation for light beams.
• Enables new possibilities for angular-momentum-based light communication, 3D particle manipulation, and optomechanical devices.