Heidelberg, Germany – Scientists at the Max Planck Institute for Medical Research have developed the world’s first all-optically controlled phased-array system for ultrasound, a breakthrough that could reshape medical therapies, particle manipulation, and tissue engineering. The study, led by Dr. Rahul Goyal and supervised by Prof. Dr. Peer Fischer, was published last week in Nature Communications.
Conventional ultrasound arrays are limited by their reliance on thousands of individually powered electronic circuits, making it nearly impossible to−scale to larger, more powerful systems. The new approach, called the Optically Programmable Array of Transducers (OPAT), overcomes this challenge by using light instead of wires to control ultrasound generation.
The researchers have developed a light-activated phase shifter, which is an analog circuit for high frequency operation based on photoresistive elements coupled with passive electronic devices in a cascaded architecture. The electrical circuit converts an optical intensity into a precisely phase shifted electrical signal, and permits the phase to be continuously tuned with phase shift of up to 2π. This is in contrast to current architectures, which do not achieve a net phase shift of 2π and which further operate with low tuning resolution (> 22.5◦)
With OPAT, a single amplifier drives the entire array, while light patterns projected onto photoresponsive phase shifters dynamically tune the output of each transducer. This enables the system to create highly complex ultrasound fields, switch between multiple focal points in real time, and even generate advanced waveforms such as acoustic vortex beams.
“Our architecture provides a fundamentally new way of shaping ultrasound,” said Dr. Rahul Goyal, lead author of the study. "Because the control is optical, the system is massively scalable. We can imagine building very large arrays capable of producing powerful and spatially complex ultrasound fields for biomedical and industrial applications".
The researchers demonstrated:
- Single-source driving: One amplifier powers the entire array, simplifying design.
- Continuous optical phase control: Each element can be tuned across a full 2π range using light.
- Scalability: Optical addressing eliminates wiring complexity, paving the way for very large arrays.
- Dynamic reconfigurability: Ultrasound wavefronts can be reprogrammed in real time, like projecting a “movie” of sound.
Applications range from non-invasive brain therapies and targeted drug delivery, to cell manipulation for tissue engineering and advanced non-destructive material testing. Because of its simple, analog design, optical addressing, and superior phase control, this novel approach paves the way for scalable transducer arrays and the generation of high-intensity, spatially-complex ultrasound fields.
The study, All-optically controlled phased-array for ultrasonics is available open access in Nature Communications.
