Modern acoustics at the extremes of microscale and macroscale

As a subdiscipline of physics, classical acoustics has reached a developmental plateau in its fundamental theories and conventional applications. However, its convergence with modern physics and intelligent methodologies has sparked revolutionary advancements in extreme microscale and extreme macroscale domains. This comprehensive review examines state-of-the-art acoustic field manipulation and its cutting-edge progress in both extreme microscopic biophysics and extreme macroscopic geophysical exploration. At the microscale, leveraging acoustic metamaterials, microbubble dynamics, and acoustic streaming effects, breakthroughs have been achieved in deep subwavelength diffraction imaging and precise manipulation at nanoscale with extreme subwavelength resolution. These advancements drive transformative biophysical innovations, including mechanical loading of biomolecules and ion channel protein regulation, while fostering emerging technologies such as sonogenetics and noninvasive ultrasonic brain-computer interfaces. In macroscale applications, full-waveform inversion enhanced by deep learning has significantly improved the accuracy and efficiency of subwavelength imaging and detection for geological interfaces at depths exceeding 10000 m in the Earth’s crust and oceans, laying a robust technical foundation for resource exploration and planetary interior studies. In the future, acoustics is poised to disruptive technologies across artificial structures/devices, noninvasive brain-computer interfaces, cellular/molecular manipulation, micro-nano imaging, targeted drug delivery, and planetary interior characterization. Its wavelength-adaptive multiscale integration will continue to promote profound interdisciplinary convergence among physics, biology, and information science.