IR Spectroscopy: A Promising Technique for Glass Analysis in Forensic Identification . By : Brian Vlaisavich, Biology, Junior, Lewis University Pradip Patel, Biology, Junior, Lewis University. Sponsor: Dr. Salim M. Diab, University of St. Francis and Lewis University . Objective .
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IR Spectroscopy: A Promising Technique for Glass Analysis in Forensic Identification
Brian Vlaisavich, Biology, Junior, Lewis University
Pradip Patel, Biology, Junior, Lewis University
Sponsor: Dr. Salim M. Diab, University of St. Francis and Lewis University
1. consists of a source, beamsplitter, two mirrors, laser, and detector.
2. beamsplitter splits the beam into two parts.
3. One part is transmitted to a moving mirror; other part is reflected to a fixed mirror.
4. The moving mirror moves back and forth at a constant velocity. This velocity is timed according to the very precise laser wavelength in the system which also acts as an internal wavelength calibration.
5. The two beams are reflected from the mirrors and recombined at the beamsplitter.
6. The beam from the moving mirror has traveled a different distance than the beam from the fixed mirror.
7. When the beams are combined an interference pattern is created, since some of the wavelengths recombine constructively and some destructively.
8. This interference pattern is called an interferogram.
9. This interferogram then goes from the beamsplitter to the sample, where some energy is absorbed and some is transmitted.
10. The transmitted portion reaches the detector.
11. The detector reads information about the wavelengths in the infrared range simultaneously.
H2O & CO2
All produced distorted spectra.