31 Aug 2005
Scientists design an optical microscope that overcomes the trade-off between field-of-view and resolving power.
A trio of researchers from Rensselaer Polytechnic Institute, US, have unveiled an optical microscope design that they say overcomes the inherent trade-off between field-of-view and resolving power found in traditional instruments. (Optics Express 13 6504)
Called an Adaptive Scanning Optical Microscope (ASOM), the Rensselaer design combines a high-speed steering mirror, a custom-designed scanner lens, a MEMS deformable mirror and imaging optics. The team's calculations suggest that an effective field-of-view diameter of 40 mm and a resolution of 1.5 microns are achievable.
According to the team, its microscope suits applications that require high-speed or flexible imaging such as biological and medical research into spatial-temporal or rare events or monitoring precision assembly of micron-sized parts.
"The traditional optical microscope makes use of static optical components and the layout has been known for centuries," researcher Ben Potsaid told Optics.org. "While the ASOM makes use of optical components which have been used before, its improved performance is achieved by including active and dynamic components in the optical path and the unique way these components are combined."
The ASOM operates by taking a sequence of spatially-displaced images in rapid succession using a 2D steering mirror. As well as the large effective field of view and high resolution, the advantages of this setup are said to be a fast image acquisition rate and the ability to keep the sample stationary.
The acquired images are then recombined into a large composite mosaic of the scene. "We have not written any software to combine the images at the moment," said Potsaid. "But we will do in future and our goal is to create a seamless image mosaic in real-time."
To test their ideas, Potsaid and his colleagues have built a simplified prototype which they call a Scanning Optical Mosaic Scope (SOMS). Built using off-the-shelf optics, the team used the SOMS to visualise living cells and were able see events such as cell division (mitosis).
"The immediate goal of the research is to construct a fully operational and high-performance ASOM prototype and demonstrate its advantages in scientific, medical and industrial applications," said Potsaid. "A long term goal is to deliver our technology to mainstream research and manufacturing arenas. We also hope to commercialise the ASOM."
The full design and specifications of the ASOM are detailed in the team's Optics Express paper.
Author
Jacqueline Hewett is technology editor on Optics.org and Opto & Laser Europe magazine.
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