【摘要】 在光纤光声成像技术中，检测灵敏度是决定光纤超声传感器成像质量的关键性因素之一。以小型化正交双频光纤激光器为超声敏感元件，建立更好的信号解调技术对声致相位变化进行检测，以实现高灵敏度超声检测和光声成像。引入射频域自相干解调技术对超声波引起的激光频率变化进行读取，实验结果表明，该技术具有超声响应信号放大效果，传感器的灵敏度在8～32 MHz的超声频率内获得了显著提升，将最小可检测声压从9.0 Pa降低到5.7 Pa。进一步地，将该超声检测技术应用于活体光声显微成像，发现在同等光强的激发条件下，图像信噪比获得逾4 dB的提升。该技术为光纤光声成像技术的应用拓展奠定了坚实的技术基础。更多还原

【Abstract】 The detection sensitivity of fiber-optic ultrasound sensors is crucial for image quality in fiberbased photoacoustic imaging.In this study,we employed a dual-polarization fiber laser as the acoustic sensing element and introduced radio-frequency heterodyne demodulation for sensitivity enhancement.Experimental results demonstrate that this method effectively eliminates noise from additional local radio-frequency oscillation sources.The proposed technique achieved an improved sensitivity,evidenced by a noise-equivalent pressure(NEP) of 9.0 Pa,compared to the 5.7 Pa offered by previous approaches within the frequency range of 8-32 MHz.Furthermore,applying this sensor to photoacoustic microscopy resulted in a signal-to-noise ratio enhancement of over 4 dB.The heterodyne detection technology significantly improves the sensitivity and image signal-to-noise ratio of fiber-optic sensors,facilitating the application of fiber-based photoacoustic imaging.更多还原