文献类型：期刊文献

英文题名：Coordinated Optical Absorption Modulation for Frequency Downshifting in Fiber-Optic Photoacoustic Transducers

作者：Liang, Tiantian[1]; Li, Cheng[1,2]; Li, Jing[3]; Lu, Shanshan[1]

第一作者：Liang, Tiantian

机构：[1] Beihang University, School of Instrumentation and Optoelectronic Engineering, Beijing, 100191, China; [2] Beihang University, Shenzhen Institute, Shenzhen, 518063, China; [3] Beijing Union University, Smart City College, Beijing, 100101, China

第一机构：Beihang University, School of Instrumentation and Optoelectronic Engineering, Beijing, 100191, China

通讯机构：[1]Beihang University, School of Instrumentation and Optoelectronic Engineering, Beijing, 100191, China;[3]Beijing Union University, Smart City College, Beijing, 100101, China|[1141734]北京联合大学智慧城市学院;[11417]北京联合大学;

年份：2026

外文期刊名：IEEE Sensors Journal

收录：EI(收录号：20261720594451)

语种：英文

外文关键词：Excited states - Fiber optic sensors - Fiber optics - Film preparation - Frequency modulation - Light modulation - Optical films - Optical signal processing - Plastic films - Structural health monitoring - Transducers

摘要：Driven by emerging demands in biomedical neuromodulation and structural health monitoring, low-frequency fiber-optic photoacoustic (PA) transducers have attracted increasing attention. However, achieving low-frequency excitation typically comes at the cost of non-negligible pressure loss, which constrains practical utility. To address this challenge, this work proposes a two-stage frequency downshifting method based on coordinated optical absorption modulation of the PA film. The former stage performs material-level modulation by adjusting the optical absorption coefficient to a moderately low value through optimized PA material formulation, reducing the center frequency from 16.2 MHz to 11.0 MHz with merely 0.88 dB pressure loss. The latter stage employs structural-level modulation by engineering the optical absorption profile through a multilayered PA film, where time-delayed superposition of sub-signals effectively broadens the PA waveform. In the optimized five-layered film structure, the average center frequency is further reduced to 4.9 MHz with an additional pressure loss of 1.29 dB. Overall, the proposed method achieves a total frequency downshift of 11.3 MHz with a total pressure loss of only 2.17 dB, resulting in a frequency downshift-to-pressure loss ratio (FDPL) of 5.21 MHz/dB, demonstrating an effective route toward low-frequency PA signal generation with minor pressure loss. ? 2001-2012 IEEE.