In this report we present a novel photoacoustic (PA) modality using pulsed chirp excitation at a fixed wavelength and spectral analysis based on frequency-domain (FD) processing. We introduce Truncated Correlation Photoacoustic Coherence Tomography (TC-PACT), a PA axial resolution enhancement methodology, with an application to closely stacked subsurface multilayers of plexiglass coated with a thin layer of graphite acting as surface absorber. The experimental results demonstrated that the SNR and the axial resolution were higher in TC-PACT than in conventional FD photoacoustics. A ns pulsed laser was also used as PA excitation source with axial resolution results found to be commensurate with TC-PACT. However, the separation distance between adjacent absorbers when the latter approached the axial resolution limit of the transducer was only resolved in TC-PACT compared to pulsed laser PA owing to the lower uncertainty in the former modality involved in determining the location of the absorbers.

在此报告中，我们介绍了一种使用固定波长的线性调频脉冲激发和基于频域（FD）处理的光谱分析的新型光声（PA）形式。我们引入了截断相关光声相干断层扫描（TC-PACT），一种PA轴向分辨率增强方法，并将其应用于紧密堆叠的有机玻璃表面多层涂层，该多层有机玻璃涂层有薄薄的石墨层作为表面吸收剂。实验结果表明，TC-PACT的信噪比和轴向分辨率均高于常规FD光声技术。ns脉冲激光也用作PA激发源，其轴向分辨率结果与TC-PACT相称。然而，