Fig. 1. The concept of CLAM.

a 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. b Virtual source generation (O_k) by the “infinity mirror”. Using ray tracing, the kth beamlet decomposed from the incident light cone follows a total of 2k reflections between the angle-misaligned mirror pair and is retroreflected back to the entrance O (the solid line is the forward path, and the dotted line is the backward path). Furthermore, there is a light path, called the cardinal mode/ray, along which the forward and backward paths are overlapped (red rays). There are other sets of light paths within the kth beamlet satisfying the condition of 2k reflections. However, these beamlets follow slightly different trajectories after the entrance O (blue rays) such that their forward and backward paths are not overlapped. These light rays return to the entrance O but with a minute lateral shift from the cardinal ray. In effect, the kth retroreflected beamlet can be considered as a “light fan” diverging from a virtual source with a very low numerical aperture (≪0.1) located at O_k. c 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. d Workflow of the image reconstruction of CLAM (for a volumetric image of a branching blood vessel).