Adaptive optics tracks microstructures

In its conventional form, the optical microscope is a trade-off between resolution and field of view. A new optical-microscope design combines a high-speed steering mirror, a custom-designed scanner lens, a MEMS deformable mirror, and additional optics to enlarge the field of view while preserving resolving power and operating at a high image-acquisition rate to capture a mosaic of images. This adaptive scanning optical microscope is being developed by Benjamin Potsaid, a research scientist, and colleagues at the Rensselaer Polytechnic Institute Center for Automation Technologies and Systems (Troy, NY, USA; www.cats.rpi.edu).

The team has built a simplified prototype of the microscope using standard lenses from ThorLabs (Newton, NJ, USA; www.thorlabs.com), a Sony (Park Ridge, NJ, USA; www.sony.com/videocameras) XC-77BB CCD camera, Matrox (Dorval, QC, Canada; www.matrox.com/imaging) Meteor-II frame grabber, and a Texas Instruments (Dallas, TX, USA; www.ti.com) DSP-based board. A Boston Micromachines (Watertown, MA, USA; www.bostonmicromachines.com) μDM100 deformable mirror will be installed in the next-generation microscope to correct for optical wavefront aberrations.

The basic approach has been demonstrated in micro-assembly and biological observation tasks. In the first task, a shape memory alloy microgripper moves between two fixed objects in the workspace. The microscope automatically tracks the microgripper with a 3 × 3 image mosaic while also including the two stationary objects in the scan pattern, demonstrating the capability to nearly simultaneously monitor and track multiple stationary and moving objects within a workspace.