Graduation date: 2005

To augment the monitoring capabilities of a Balzers 760 coating chamber, we replaced the simple, single wavelength optical monitor with a wide-band scanning monochromator system which records transmission data over the visible region of the spectrum. The system is controlled by an IBM-PC. The same computer is also interfaced to a quartz crystal monitoring system which was purchased with the Balzers chamber. The scanning monochromator system required a new brighter light source to deliver sufficient signal to the detector array through the more complex, dispersive optical train. Above the chamber the filter and the photomultiplier pair were removed, and replaced by a flat mirror which diverts the beam horizontally into the scanning monochromator system. The beam passes first through a telescope-slit configuration onto a Jobin-Yvon holographic grating, built to disperse the 400-800 nm band of which we use approximately 360 nm. This reflective grating images the spectrum of the slit onto a Fairchild CCD array, which consists of 1728 elements. These elements are then averaged into 173 data points and recorded by the IBM-PC. The 173 data points allows us a wavelength resolution of about 2 nm. The IBM incorporates a Tecmar A/D board in accepting data from both the quartz crystal monitor and the scanning monochromator system. Although the system is capable of recording data at a faster rate, it is generally stored once every three seconds. This is adequate since at normal deposition rates this gives us information every 10 - 20 Angstroms of deposited material. The system has been used in several applications which will be discussed in this dissertation. They include in situ measurements of water adsorption into a film, derivation of optical constant profiles during the film deposition, both of which may lead us to a better understanding of the growth of a thin film. The monochromator has also been used to analyze the components of a multilayer coating by monitoring the film's transmission spectra while it was sputter-etched off. The extension of the system into the ultraviolet region of the spectrum and some future applications are also considered.

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A three-beam lateral shearing interferometer has been developed. The three-beam shearing interferograms consist of two sets of fringes, one of which acts as a carrier whose intensity is modulated by the second set. The depth of modulation is directly proportional to the phase difference between the middle beam and the outer beams. Phase errors on the order of π/2 cause every other fringe to go from complete dark to complete bright. Therefore, phase errors much smaller than π/2 can be detected. The three-beam interferometer is implemented in three ways: (1) thin film thickness measurement, (2) surface roughness measurement, and (3) surface figure measurement. The three-beam interferometer implemented to measure thin film thickness and surface roughness is accurate to 25 Å. Surfaces with different microstructure are characterized. We have found that each of those surfaces may have one or more of the following: (1) random roughness, (2) slow waviness, and/or (3) periodic structure. The three-beam interferometer is also implemented for testing optical surfaces. The three-beam interferometer is more capable in detecting small zonal errors than the two-beam interferometer. Three-beam interferograms of different surfaces are produced and analyzed. The three-beam interferometer has many advantages: (1) it is a stable, common path interferometer, (2) white light can be instead of coherent light to get rid of the effects of speckle and dust particles, and (3) it is a very low cost interferometer.