Optomechanical time-domain analysis (OMTDA) is a novel approach to measure distributed acoustic impedance of surrounding media with a high spatial resolution based on coherent forward stimulated Brillouin scattering probing. However, the spatial resolution is still limited by the polarization noise and influence of activation pulse. In this Letter, we propose a polarization separation based OMTDA to further improve the resolution. By isolating the acoustic activation and probing process in orthogonal polarization states, the backward Brillouin scattering of an activation pulse is effectively suppressed. Accompanied with the reduced polarization fluctuation brought by polarization-maintaining fiber, a spatial resolution of 0.8 m is experimentally demonstrated over a 34-m-long fiber and the precise distinction between air and alcohol is realized.

中文翻译：

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亚米级分辨率的偏振分离辅助光机时域分析

光机时域分析 (OMTDA) 是一种基于相干前向受激布里渊散射探测以高空间分辨率测量周围介质分布式声阻抗的新方法。然而，空间分辨率仍然受到极化噪声和激活脉冲影响的限制。在这封信中，我们提出了一种基于偏振分离的 OMTDA，以进一步提高分辨率。通过隔离正交极化状态下的声学激活和探测过程，激活脉冲的后向布里渊散射被有效抑制。伴随着保偏光纤带来的偏振波动减小，在34米长的光纤上实验证明了0.8米的空间分辨率，实现了空气和酒精的精确区分。