DECEMBER 1998 REPORT FOR

W. CHARLES SYMONS, III

Although I successfully completed my Ph.D. qualifying examination in October, a revised dissertation proposal was requested. This proposal was completed in early November and can be viewed online. For this proposal, a coarse polystyrene spectrum was collected as seen in Figure 1 below. The collection of this polystyrene spectrum serves two purposes. First, it provides proof that a near-IR spectrum can be collected utilizing a NSOM instrument. Secondly, the polystyrene spectrum will serve as a reference to validate that the system is properly calibrated and working as expected. To this end, the coarse spectrum can be compared to the complete near-IR spectrum in Figure 2, which was collected by the lab's Bran and Lubbe spectrometer. By comparing these two figures, it can be seen that the NSOM instrument reproduced the falling edge of the main 1680nm peak along with the rise of the shoulder to the right of this peak.

Figure 1: Coarse NSOM Polystyrene Spectrum.

Figure 2: Reference Polystyrene Spectrum.

At this point, the spectrum obtained with the current system is relatively coarse due to the fact that the wavelength tuning board for the near-IR laser diode has yet to be received. Due to this difficulty, the wavelength was tuned by hand which will resulted in an inability to select as many wavelengths. Recently, it has been discovered in the laser diode manual that a second wavelength tuning capability exists. This capability allows for varying the laser's piezo voltage, which in turn, results in a directly varying output wavelength. In fact, a LabView program was recently developed to output a variable voltage in order to tune the diode's output wavelength. It is anticipated that this program will be tested and utilized to collect enhanced spectra within the next few weeks.