Revibro’s Tunable Focus Mirrors (TFM) provide rapid, agile focus control for applications requiring precise z-axis scanning. Like liquid lenses or Electrically Tunable Lenses (ETLs), Revibro’s TFMs are controlled electrically to change the shape of the surface—but are 10-100x faster.
Tunable Focus Mirror
Our 4mm* TFM are reflective membranes placed over concentric electrode rings. Applying a voltage between the mirror and electrodes changes the mirror shape to vary the focal length from infinity (flat mirror) to less than 60mm (or anywhere in between) in less than 250µs.
* other diameters available by request.
Our CHV400-4 controller provides electronic closed-loop position control for the TFM, with no extra optics or detectors. Closed-loop control provides precise, repeatable focus control with microsecond response times.
With a step response time less than 250µs, Revibro’s tunable mirrors are orders of magnitude faster than other z-stack actuators. In galvanometer-based systems, focus stepping is concurrent with the galvanometer‘s retrace. Thus, with no delay before the next image in a stack, acquisitions occur at the full video rate—limited only by the speed of the X-Y scanners.
The impact on imaging is significant; a “sawtooth” scan type is no longer necessary to mitigate step jitter, and the “step” scan type works directly. Additionally, all delays (flyback time, actuator lag) are zero, resulting in real-time volume acquisition.
Our mirrors are available with up to five separate concentric electrodes, tuning the shape of the mirror surface with an independent actuation voltage applied to each zone. The result is the ability to tune out both primary Z(4,0) and secondary Z(6,0) spherical aberrations in the optical system.
In addition, mirror shape can change extremely quick, enabling real-time aberration corrections of sample-induced aberrations that change with focal position.
Example 4-zone concentric
electrode on the substrate
Each zone has independent voltage control which allows aberration correction on the continuous mirror surface.
Negative primary spherical tuning (flat bottomed mirror shape)
Zernike polynomials (mm)
Positive primary spherical tuning (cone shaped mirror)
Zernike polynomials (mm)
When used in imaging applications like compact cameras or machine vision, Revibro’s Tunable Focus Mirror changes focus between video frames! Capturing full frame rate video with each frame at a different position is now possible.
Watch the video demoing a single camera using Revibro's TFM to change focus between frames.
Laser focus control
Compact, high-speed imaging