A-scan fluorescence microscopy for rapid cross-sectional imaging

This paper presents a microscopy technique that can perform snapshot depth resolved optical imaging in the same manner as A-scan in ultrasound imaging and optical coherence tomography. In this technique, a laser line along the axial dimension is used to illuminate a sample to create a fluorescent line object. By transforming the line object along the axial dimension (Z) to a ring image on the lateral dimensions (X-Y) using a full cone mirror, common optics can be used to relay and acquire the ring image precisely. Then, by converting half of the ring image back to a line image using a half cone mirror, the opening side of the half cone mirror allows the line image, which contains the full depth resolved information of the line object, to be taken in one snapshot. This eliminates the requirement of axial scanning in traditional depth resolved imaging techniques such as confocal microscopy to obtain the same information. The technique is demonstrated by imaging fluorescent microspheres of different diameters. This technique offers a simple alternative to traditional depth resolved imaging techniques such as confocal microscopy and light sheet microscopy. It is particularly useful in imaging samples with multiple layers in which multiple A-scans or a few B-scans are sufficient to represent the entire sample.