General schematic of the CLAM setup. The setup mainly consists of four key parts: (1) an angle-misaligned mirror pair (or “infinity mirror”) for the generation of the beamlet array; (2) a light-sheet encoder for the light modulation of the beamlet array with the temporal codes; (3) relay optics for shaping the beamlet array to the light-sheet array; and (4) imaging optics in which the detection arm and illumination arm are orthogonal to each other. Virtual source generation ( ) by the “infinity mirror”. Using ray tracing, the kth beamlet decomposed from the incident light cone follows a total of 2 reflections between the angle-misaligned mirror pair and is retroreflected back to the entrance (the solid line is the forward path, and the dotted line is the backward path). Furthermore, there is a light path, called the , along which the forward and backward paths are overlapped (red rays). There are other sets of light paths within the th beamlet satisfying the condition of 2 reflections. However, these beamlets follow slightly different trajectories after the entrance (blue rays) such that their forward and backward paths are not overlapped. These light rays return to the entrance but with a minute lateral shift from the cardinal ray. In effect, the th beamlet can be considered as a “light fan” diverging from a source with a very low numerical aperture (≪0.1) located at . Parallelized light-sheet array illumination. As each light sheet is temporally modulated with a unique code generated by the light-sheet encoder, the fluorescence signals from different depths along the z-direction, tagged with the same temporal codes, are multiplexed and detected by the camera. Workflow of the image reconstruction of CLAM (for a volumetric image of a branching blood vessel).
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