Typical LSCMs take 3-D images of thick tissue samples by visualizing
thin slices within that tissue one layer at a time. Sometimes
scientists supplement these microscopes with spectrographs, which are
devices that measure the pattern of wavelengths, or "colors," in the
light reflected off of a piece of tissue.
This pattern of wavelengths acts like a fingerprint, which scientists
can use to identify a particular substance within the sample. But the
range of wavelengths used so far with these devices has been narrow,
limiting their uses. Not so with the new microscope developed by
physicists from the Consiglio Nazionale delle Ricerche (CNR) in Rome,
and described in a paper accepted to the AIP's new journal AIP Advances.
Unlike other combination "confocal microscope plus spectrograph"
devices, the new machine is able to gather the spectrographic
information from every point in a sample, at a wide range of
wavelengths, and in a single scan. To achieve this, the authors
illuminate the sample with multiple colors of laser light at once
– a sort of "laser rainbow" – that includes visible light
as well as infrared. This allows scientists to gather a full range of
information about the wavelengths of light reflected off of every point
within the sample.
Using this method, the researchers took high-resolution pictures of the
edge of a silicon wafer and of metallic letters painted onto a piece of
silicon less than half a millimeter wide. They also demonstrated that
it is possible to apply this technique to a tissue sample (in this
case, chicken skin) without destroying it. With further testing, the
researchers say the microscope could be used to detect early signs of
melanoma; until then, it may be useful for non-medical applications,
such as inspecting the surface of semiconductors.
"Supercontinuum ultra wide range confocal microscope for reflectance
spectroscopy of living matter and material science surfaces" is
published in AIP Advances.|