Resonant vs Polygon scanners

Here are contrasting differences between resonant and polygon scanners.

Scan Rate vs Scan Angle

A resonant scanner is designed for a fixed scan rate but the scan angle is variable.

A polygon scanner is designed for a fixed scan angle  but the scan rate is variable.

Linear vs Non-Linear scan Speed
The scan speed of a resonant scanner is constantly changing.  Like a pendulum, it is accelerating toward the center and then decelerating toward the end of the sweep.  Then it reverses the cycle.
Polygon scanners are highly engineered to scan at a constant speed.  Motors, controllers and bearings are carefully designed for very precise and smooth rotation.  The high mass of a polygon mirror has inertia which helps to maintain linear scan rates.

Bi-directional vs Uni-directional scanning
Resonant scanners have a bi-directional scan.
Polygon scanners have a uni-directional scan.

Size
Resonant scanners are very compact.  The mirror and motion system are typically very small.
Polygon scanners are, by nature, much larger.  A polygon mirror has many mirrors cut around a metal disc.  It requires a significant motor to overcome the windage of the polygon mirror.  However, some polygon scanners are designed for compact format.  GECKO ULTRA-COMPACT POLYGON SCANNERS

Aperture Size
The top speed of both the resonant scanner and the polygon scanner are a function of aperture size.  Both technologies are similar in that a smaller aperture mirror is capable of higher scan speed.

Laser Damage Threshold
Polygon scanners are the best technology for laser damage threshold with high power lasers.  LASER DAMAGE THRESHOLD

Each technology has its strengths and weaknesses.  Resonant scanners tend to be found in low power laser applications where small size is critical.  Polygon scanners are common in low power and high power laser applications where fast and constant scan speed are required.