Photoacoustic imaging (PAI) takes advantage of both optical and ultrasound imaging properties to visualize optical absorption with high resolution and contrast. Photoacoustic microscopy (PAM) is usually categorized with all-optical microscopy techniques such as optical coherence tomography or confocal microscopes. Despite offering high sensitivity, novel imaging contrast, and high resolution, PAM is not generally an all-optical imaging method unlike the other microscopy techniques. One of the significant limitations of photoacoustic microscopes arises from their need to be in physical contact with the sample through a coupling media. This physical contact, coupling, or immersion of the sample is undesirable or impractical for many clinical and pre-clinical applications. This also limits the flexibility of photoacoustic techniques to be integrated with other all-optical imaging microscopes for providing complementary imaging contrast. To overcome these limitations, several non-contact photoacoustic signal detection approaches have been proposed. This paper presents a brief overview of current non-contact photoacoustic detection techniques with an emphasis on all-optical detection methods and their associated physical mechanisms.

光声成像 (PAI) 利用光学和超声成像特性，以高分辨率和对比度可视化光吸收。光声显微镜（PAM）通常归类为全光学显微镜技术，例如光学相干断层扫描或共焦显微镜。尽管 PAM 具有高灵敏度、新颖的成像对比度和高分辨率，但与其他显微镜技术不同，PAM 通常并不是一种全光学成像方法。光声显微镜的显着局限性之一是它们需要通过耦合介质与样品进行物理接触。对于许多临床和临床前应用来说，样品的这种物理接触、耦合或浸入是不期望的或不切实际的。这也限制了光声技术与其他全光学成像显微镜集成以提供互补成像对比度的灵活性。为了克服这些限制，已经提出了几种非接触式光声信号检测方法。本文简要概述了当前的非接触式光声检测技术，重点介绍了全光学检测方法及其相关的物理机制。