Deep photoacoustic imaging with metasensors probed by dual optical frequency combs

• Applicant: Dr.-Ing. Maryna Meretska
• Subject Area: Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology ; Biophysics ; Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 568935442

METASENSOR aims to advance photoacoustic tomography by enabling the optical detection of high-frequency ultrasound (up to 100 MHz). This is essential to resolve single cells, which emit peak photoacoustic signals in this frequency range. The approach relies on mechanically-induced shifts of high-Q optical guided mode resonances. Current optical resonators fail to combine ultra-high Q factors, broadband operation, and scalable array integration with free-space interrogation. Fabrication-induced spectral resonance shifts make it difficult to align all resonances to the same wavelength, which limits temporal resolution, since the interrogation wavelength has to be set individually for each sensor. METASENSOR will address these limitations by developing compact optical resonator arrays (50 × 50 μm² per element) with Q factors exceeding 10⁵. These will be interrogated using dual optical frequency combs, enabling readout with an identical optical source despite spectral inhomogeneity, with potential multiplexing capability. This will unlock high-speed photoacoustic imaging with cellular resolution and large fields of view. Ultimately, the technology could enable chronic imaging for non-invasive long-term functional brain activity recording deep into biological tissues in animal models.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partners: Privatdozent Dr. Thomas Chaigne, Ph.D.; Professor Dr. Arnaud Mussot