摘要
We investigated an acoustic-vortex-based dynamic lens capable of manipulating light underwater by generating pressure-tunable annular cavitation structures. High-speed imaging revealed the presence of stable bubble rings whose mean thickness increased from similar to 2.4 to 3.39 mm as the input pressure increased from 2.6 to 16.3 MPa. Optical measurements confirmed that higher pressures shortened the effective focal length of the lens, consistent with a larger refractive-index gradient. Ray-tracing simulations using a gradient-index (GRIN) lens model derived from the bubble geometry quantitatively reproduced the observed focusing behavior. These findings clarify the generation mechanism of such lenses and demonstrate their potential as a dynamically reconfigurable optical element for use in underwater applications. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.