3D Movies of Microscopic Systems

Juli 29, 2009

Physicists at New York University (NYU), US have developed a technique to record three-dimensional movies of microscopic systems, such as biological molecules, through holographic video. The technique, developed in the laboratory of NYU Physics Professor David Grier, is comprised of two components: making and recording the images of microscopic systems and then analyzing these images. To generate and record images, the researchers created a holographic microscope. It is based on a conventional light microscope, which uses a collimated laser beam instead of on an incandescent illuminator.
When an object is placed into path of the microscope’s beam, the object scatters some of the beam’s light into a complex diffraction pattern. The scattered light overlaps with the original beam to create an interference pattern reminiscent of overlapping ripples in a pool of water. The microscope then magnifies the resulting pattern of light and dark and records it with a conventional digital video recorder. Each snapshot in the resulting video stream is a hologram of the original object. Unlike a conventional photograph, each holographic snapshot stores information about the three-dimensional structure and composition of the object that created the scattered light field. The recorded holograms appear as a pattern of concentric light and dark rings.
For analyzing the images the researchers based their work on a quantitative theory, the Lorenz-Mie theory, which maintains that the way light is scattered can reveal the size and composition of the object that is scattering it.
The application of the technique ranges from research in fundamental statistical physics to analyzing the composition of fat droplets in milk.
www.nyu.edu

In the microscope, a laser beam illuminates the sample. Light scattered by the sample creates an interference pattern which is magnified and recorded. Then measurements of the particle’s position, size, and refractive index are obtained.

In the microscope, a laser beam illuminates the sample. Light scattered by the sample creates an interference pattern which is magnified and recorded. Then measurements of the particle’s position, size, and refractive index are obtained.


Microscopy and Microanalysis Conference

Mai 18, 2009

The Microscopy & Microanalysis 2009 Conference, which is the annual meeting of the Microscopy Society of America and the Microbeam Analysis Society, will take place from July 26-30, 2009 in Richmond, Virginia, US. This year’s conference is co-sponsored by the International Metallographic Society. The event addresses to scientists, technologists and students who use microscopy or microanalysis in their research. Topics of the full-day short courses include electron tomography, digital imaging, FIB methodologies, variable pressure and environmental SEM imaging and analysis, cryo EM and interpretation of metallographic microstructures. Over 30 symposia focus on applications in both the biological and physical sciences as well as recent and emerging trends in instrumentation and techniques. Further, contributed sessions, tutorial sessions, poster presentations as well as round-table discussions will be held. www.internationalmetallographicsociety.org
http://mm2009.microscopy.org