Could SPIM Opens News Eyes for Nano-Microscopy?
A new Scanning Photoionization Microscope (SPIM) has been unveiled for analyzing the make-up and properties nano-electronics and nanoparticles. The SPIM device, which developers concede is “still in its infancy,” was demonstrated in October by National Institute of Standards and Technology and the University of Colorado (Boulder).
JILA, a joint institute between NIST and University of Colorado are developing SPIM
How SPIM Works, How SPIM is Made
By comparing SPIM images of nanostructured gold films to scans using atomic force microscopy, which profiles surface topology, the researchers confirmed the correlations and physical mapping accuracy of the new technique. They also determined that lines in SPIM images correspond to spikes in electron energy, or current, and that contrast depends on the depth of electrons escaping from the metal as well as variations in material thickness.
The SPIM apparatus, built by JILA, includes
- Capacity to combine high-spatial resolution of optical microscopy with the high sensitivity to subtle electrical activity made possible by detecting the low-energy electrons emitted by a material as it is illuminated with laser pulses.
- Features a moving optical microscopy stage in a vacuum, an ultra fast near-ultraviolet laser beam that provides sufficient peak power to inject two photons (particles of light) into a metal at virtually the same time,
- Includes equipment for measuring the numbers and energy of electrons ejected from the material.
Work is continuing to further develop the method, which may be able to make chemically specific images, for example, if the lasers are tuned to different colors to affect only one type of molecule at a time. The SPIM research is supported by the Air Force Office of Scientific Research and National Science Foundation. (O.L.A. Monti, T.A. Baker and D.J. Nesbitt. 2006).