As a label-free, non-invasive, and high-contrast imaging technology, photoacoustic microscopy (PAM) is widely used in biomedical science. However, due to the restriction of diffraction limit, the optical resolution of PAM has not been effectively improved. In this paper, in order to break the diffraction limit, a patterned competition based on saturable transient absorption effect is introduced to realize the super-resolution imaging into the conventional photoacoustic microscopy. We have provided a physical model of photoacoustic microscopy based on transient absorption saturation difference (TASD-PAM) and verified its effectiveness by analyzing the photophysical properties of our sample and imaging it with a sub-diffraction lateral resolution. Compared to reported pump-probe microscopy, which is based on stimulated emission depletion or ground-state depletion process, our method can realize the label-free super-resolution imaging of dark materials that cannot emit fluorescence. This technique enables observing the microstructure of dark materials in a way that defies the diffraction limit, which will expand the application range of photoacoustic microscopy and open up a new way for super-resolution imaging.

光声显微镜（PAM）作为一种无标记、非侵入性、高对比度的成像技术，广泛应用于生物医学领域。然而，由于衍射极限的限制，PAM的光学分辨率并没有得到有效的提高。在本文中，为了突破衍射极限，基于可饱和瞬态吸收效应的图案化竞争被引入，以实现传统光声显微镜的超分辨率成像。我们提供了基于瞬态吸收饱和差 (TASD-PAM) 的光声显微镜物理模型，并通过分析我们样品的光物理特性并使用亚衍射横向分辨率对其进行成像来验证其有效性。与报道的泵浦探针显微镜相比，基于受激发射耗尽或基态耗尽过程，我们的方法可以实现对不能发射荧光的暗物质的无标记超分辨率成像。该技术能够以一种无视衍射极限的方式观察暗物质的微观结构，将扩大光声显微镜的应用范围，为超分辨率成像开辟一条新途径。