Fig. 5: Ultrafast random-access focus control in a large 3D space.
a Simplified experimental schematic for ultrafast 3D focus control using two cameras (CAM1 and CAM2) located on axially separated target planes of z = 3 mm and 3.2 mm. Within a camera exposure time of 1 μs, the line beam scans over ~30 columns and undergoes serial wavefront modulation in the setting of Mcol = 2. b Focal spots reconstructed from serial wavefront modulation on the two planes within the time period of 1 μs. Contrast of focal spots in these images was improved due to the nine-fold averaging by physically translating the scattering medium and by using the previously developed digital background cancellation method51. Note that the actual instantaneous focal contrast is as shown in the left panel of Fig. 4b. Scale bar: 5 μm. c Simplified experimental schematic for large-volume and frequency-modulated focus control with two single-mode optical fibers (SMF1 and SMF2). Focal spots coupled into optical fibers are detected by photomultiplier tubes (PMT1 and PMT2) d Optical signals for focal spots simultaneously modulated at different frequencies that were measured through SMF1 and SMF2 placed at (x, y, z) = (0, 2.5, 2) mm and (0, 0, 2) mm, respectively. e Frequency spectrum of the optical signals in (d).
