Highly Integrated Fiber-Optic Transducer for Dual-Modality Imaging: Advancing Generating Efficiency and Bandwidth

Photoacoustic (PA) and ultrasound (US) dual-modality imaging, combining the high resolution of PA imaging and the high penetration depth of US imaging, has long been envisioned as an edge tool. This complementary duality holds transformative potential for applications ranging from lymph node characterization to intravascular diagnostics. Yet, conventional dual-modality imaging systems remain constrained by the limited integration complexity. This study pioneers a paradigm-shifting imaging system with a highly integrated single-fiber-based PA-US dual-modality transducer. The core of the system lies in a nontoxic ultraviolet glue-dye (UV-dye) transducer design, which exhibits wavelength-selective optical properties, enabling efficient US generation and PA excitation simultaneously. This transducer architecture achieves an ultrasound generation efficiency of 0.04 MPa mJ–1 cm2 with a 37.1 MHz bandwidth excited by a 532 nm laser pulse, which are 67% and 106% higher than the existing transducer, respectively. Experimental validation is conducted on the established integrated PA-US dual-modality system, in which the lateral resolutions of US and PA imaging modalities are calibrated to be as high as 90 and 125 μm, while axial resolutions are, respectively, verified as 60 and 55 μm at a depth of 2.5 mm, effectively equipped as an intelligent microscope for biological tissue imaging. Further, the system successfully reconstructs dual-modal images of ex vivo tissues that transcend traditional single-mode limitations, revealing detailed structural and chromophore information on the biological tissue. The proposed all-fiber dual-modality imaging system owns the capability of high resolution and sufficient tissue details, demonstrating its broad application prospect in angiography and oncology.