For laser scanning and adaptive optics, there are often tradeoffs in terms of speed, range, and beam size. Pick two, because you can’t have all three due to the inertia limits of high-speed laser scan mirrors, deformable mirrors, and other components.
Whether you are a neuroscientist trying to map thousands of neurons firing across the brain or a manufacturer 3D-printing a complex turbine part, the limit has always been the scanner.
Resonant scanners are fast but “tight” (small angles). Galvos are “wide” but slow. This mechanical bottleneck has dictated the architecture of laser-based systems for decades. But Pacific Optica developed a scan engine that changes the math. Using a patented inertia-free scan angle multiplication (SAM) technique, our Ventana system enables high-speed scanning across massive fields of view, with large beams to ensure high numerical aperture imaging.
‘Inertia-free’ advantage: The physics of multiplication
The term “inertia-free” is the key because mass is the enemy of speed for any mechanical system. To get a wider scan angle out of a traditional mirror, you need a larger mirror or a more powerful motor. But both introduce inertia that slows the response time and creates heat.
Our technique bypasses these issues entirely. By using an optical relay that bounces the laser off a resonant mirror multiple times, the system multiplies the scan angle geometrically. A 4x multiplier, for instance, turns a modest 10-degree scan into a 40-degree scan—all while maintaining the 8- to 16-kHz speeds of the resonant scan mirror.
The core of our innovation lies in a series of folded optical relays, combined with clever instrumentation and optical design. Traditional scanning systems rely on the physical tilt of a mirror to deflect a beam. To increase the angle, you must either tilt the mirror further (limited by the mechanical properties of the resonator) or increase the mirror size (increasing inertia and slowing the system).
Our technique takes a different approach. It uses a stationary optical system to pass the laser beam across the same resonant mirror multiple times. Each “bounce” adds to the cumulative deflection. Because the additional work is done by stationary optics rather than a larger or faster moving part, the system remains inertia-free in terms of its mechanical drive.
Our team demonstrated a multiplier that could take a standard 10-degree scan and expand it significantly without sacrificing the kilohertz speeds that resonant scanners are known for. This isn’t merely a zoom effect; it’s a fundamental expansion of the system’s scan volume.