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Synthesized Acoustic Vortex-Frequency Comb via Rotational Doppler Effect.
Yurou Jia1,2, Xuan Zhang1, Suying Zhang1
1Nanjing University, Department of Physics, MOE Key Laboratory of Modern Acoustics, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Physical Science Research Center, Nanjing 210093, China.
Physical Review Letters
|April 18, 2025
Summary
Researchers developed an acoustic synthesized comb structure to control sound wave frequency and orbital angular momentum (OAM). This breakthrough enables efficient, versatile acoustic spatiotemporal beam generation for advanced applications.
Area of Science:
- Acoustic Metasurfaces
- Spatiotemporal Optics
- Nonlinear Acoustics
Background:
- Controlling light's frequency and orbital angular momentum (OAM) is vital for optical metrology and waveform generation.
- Acoustic analogs are limited by external driving dependence and low frequency conversion efficiency in nonlinear mechanisms.
Purpose of the Study:
- To present an acoustic synthesized comb structure for concurrent frequency and OAM control.
- To overcome limitations of nonlinear acoustic mechanisms regarding driving conditions and efficiency.
- To enable advanced acoustic spatiotemporal beam manipulation.
Main Methods:
- Utilizing spatiotemporal metasurfaces to create an acoustic synthesized comb structure.
- Optimizing comb structures to tailor energy distribution among OAM modes and frequency lines.
- Developing spatiotemporal metalenses based on vortex-frequency combs.
Main Results:
- Achieved concurrent control of acoustic frequency and OAM with high conversion efficiency.
- Eliminated constraints of critical driving frequency and power levels for nonlinear mechanisms.
- Demonstrated adjustable energy distribution across OAM modes for different frequencies.
Conclusions:
- The proposed acoustic synthesized comb structure offers a novel approach to acoustic spatiotemporal beam generation.
- Spatiotemporal metalenses based on vortex-frequency combs enable parallel data processing via multiple-order spatial differential operations.
- This work integrates spectral and spatial domains in acoustics, promising multifunctional imaging and advanced spatiotemporal beam applications.
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