Mechanicalscanning

Mechanicalscanning refers to methods for obtaining spatially resolved measurements or images by moving a sensor, light source, or optical element through a controlled mechanical path. Unlike electronic or computational beam steering alone, mechanicalscanning relies on physical motion to sample a scene or sample volume. Typical implementations include rotating polygon mirrors or rotating drums that redirect a laser beam across a target, galvanometer-based fast-turn mirrors that tilt about an axis, and translational stages that sweep the probe linearly or in a raster pattern. In many optical systems, a combination of a fast-scanning element (galvo) and a slower mechanical axis creates a two-dimensional scan trajectory.

Advantages include simple, robust light delivery and high instantaneous light collection along the scan line; limitations include mechanical wear, inertia, limited scanning speed and angular range, and potential vibration-induced artifacts. Precision depends on mechanical tolerances, bearing quality, and control loops.

Applications span laser scanning microscopy (confocal and two-photon) where a focused beam scans across a sample; laser barcode scanners and laser projectors; high-speed LIDAR and radar systems that use rotating or tilting optics to cover a field of view; and old or specialized printing and display technologies that rasterize images by moving a beam. Some systems combine mechanical scanning with electronic or computational methods to form composite images or 3D reconstructions.

Historical note: before widespread electronic angular scanning, mechanical scanners were the primary method to sweep beams; they remain in use where simplicity and robustness are valued or where large fields of view are needed.