Multi-beam miniaturized volumetric scanning microscopy with a single 1-dimensional actuation

Miniaturized optical imaging systems typically utilize 2-dimensional (2-D) actuators to acquire images over a 2-D field of view (FOV). Piezoelectric tubes are most compact, but usually produce sub-millimeter FOVs and are difficult to fabricate at scale. Planar piezoelectric bending actuators (`benders') are capable of much larger actuations and substantially lower cost, but inadequate for 2-D steering. We present a piezoelectric bender fiber scanning platform that exploits mechanical coupling to produce multi-millimeter scale 2-D scan coverage (2.1 x 1.5 mm) with a resolution of 12.6 um full-width at half-maximum. We extended the FOV (2.1 x 2.9 mm) by mosaicking three 2-D scans from optical fibers resonating in synchronicity across the bender. Leveraging optical coherence tomography with a long coherence length laser, we performed 3-D imaging of biological samples using depth-multiplexed imaging beams. This multi-fold improvement in scanning coverage and cost-effectiveness promises to accelerate the advent of piezoelectric scanning in compact devices such as endoscopes and headsets.