overview
The purpose of daoSPIM system is imaging a sample inside microfluidic device using light-sheet illumination and dual-view detection . The design allows simultaneous imaging from two directions (views) using a single camera sensor, by combining the two optical paths into one. This is achieved by using a knife-edge mirror (M-prism) between the arms. The figure below shows simplified arrangement in 3d (a), detailed optical layout (b), and a zoom-in of detection and excitation light rays as they pass through the glass coverslip (c, excitation shown from the right side).
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Due to the left-right symmetry of the optical train, images from both left and right objective are projected on the camera sensor simultaneously without any mechanical switching.
The optical design puts the pupil planes of the two objectives in the same space, where an adaptive optics element (deformable mirror) can compensate aberrations in two views simultaneously, without any switching between them.
Laser excitation beam enters the joined optical path via polychroic mirror M-poly. The light sheet is genarated by scanning the galvo mirror M-scan. The same galvo switches the illumination between left and right arm by adding constant bias to the scanning command. This is shown in animations below.
(a) The water-filled chamber with two objectives in open-top configuration. The microfluidic device is fixed inside the sample holder. (b) The sample holder is attached to motorized horizontal stage and manual vertical stage. (c) The folding mirror assembly. (d) The M-prism is mounted on the XYθ mini-stage. (e) The DM is fixed on a kinematic prism mount. (f) The laser scanning assembly, with yellow arrows showing laser propagation direction. (g) The system overview, with laser coming from the laser scanning assembly (yellow arrow).
The component list and their approximate costs (~100k EUR) is available in the BOM.xlsx file.