The use of portable Raman analyzers to identify unknown substances in the field has grown dramatically during the
past decade. Measurements often require the laser beam to exit the confines of the sample compartment, which
increases the potential of eye or skin damage. This is especially true for most commercial analyzers, which use 785
nm laser excitation. To overcome this safety concern, we have built a portable FT-Raman analyzer using a 1550 nm
retina-safe excitation laser. Excitation at 1550 nm falls within the 1400 to 2000 nm retina-safe range, so called
because the least amount of damage to the eye occurs in this spectral region. In contrast to wavelengths below 1400
nm, the retina-safe wavelengths are not focused by the eye, but are absorbed by the cornea, aqueous and vitreous
humor. Here we compare the performance of this system to measurements of explosives at shorter wavelengths, as
well as its ability to measure surface-enhanced Raman spectra of several chemicals, including the food contaminant
melamine.
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