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Presents a study which examined the microstructure and composition of the silicon dioxide/titanium dioxide and digital gradient-index films using transmission electron microscopy. Growth of the digital structures; Modification of the properties of dielectric thin films; Results of Auger electron spectroscopy.

Ultrahigh vacuum studies of the interaction of 514 nm radiation from a cw Ar ion laser and its second harmonic at 257 nm with mono- and multilayer coverages of Mo(CO)6, W(CO)6, and Fe(CO)5 adsorbed on Si(111)7×7 at 90 K using thermal desorption spectroscopy (TDS), laser induced desorption spectroscopy, high resolution electron energy loss spectroscopy (HREELS), and Auger electron spectroscopy were performed. A model for the temperature rise of the sample due to cw laser heating is developed. By directly measuring the substrate temperature, these experiments were able to distinguish between photoelectronic and thermal effects active in the decomposition and desorption mechanisms of the adsorbed carbonyls. Results from TDS and HREELS show that Mo(CO)6 and W(CO)6 are molecularly adsorbed, while Fe(CO)5 partially dissociates upon adsorption. The decomposition of adsorbed Mo(CO)6 is caused by electronic excitation due to direct absorption of the 257 nm radiation. Irradiation with 514 nm radiation results in no photochemistry. The same mechanism is dominant for adsorbed W(CO)6 and Fe(CO)5; however, new excitation mechanisms are available to these molecules that lead to bonding changes in W(CO)6 and Fe(CO)5 with 514 nm irradiation. The photodecomposition products of the adsorbed carbonyls are found to be different from the gas-phase decomposition products. The surface stabilizes the adsorbed carbonyls, preventing complete removal of all the CO ligands. Desorption of CO due to photoelectronic excitation is found to occur via sequential single photon absorption and extraction of CO ligands. Evidence of clustering of carbonyl fragments was observed after 257 nm irradiation. [ABSTRACT FROM AUTHOR]

Reports the results of a series of experiments studying metal film growth by low-power ultraviolet laser photolysis of metal carbonyls. Elemental depth profiling by Auger electron spectroscopy; Mechanisms of adsorbed metal carbonyl decomposition; Comparison between the photodecomposition products of the adsorbed carbonyls and the gas-phase decomposition products.

The behavior of codeposited thin films of ZnSe/LaF(3) and Si/ZnSe has been investigated. Mixed ZnSe/LaF(3) films are polycrystalline with intermediate compositions with moderately high compressive stress (1500-2000 kg/cm(2)). Mixed Si/ZnSe films are amorphous with intermediate compositions with low compressive stress (<1000kg/cm(2)). Optical properties of the ZnSe/LaFcm(3) system vary monotonically with composition, but those of the Si/ZnSe system do not, which is explained by the possible chemical reaction of the two species.

An ultrahigh-Q, tunable optical filter with a FWHM bandwidth of 41 MHz is demonstrated. The filtering is produced by nondegenerate phase conjugation through four-wave mixing in atomic-sodium vapor. The filter is observed to have a maximum quantum efficiency of 4 x 10(-3). However, degenerate phase-conjugation experiments in sodium suggest that a quantum efficiency of greater than unity can be attained on a cw basis.

Rugate filters are optical thin film interference structures with sinusoidal refractive index profiles. Two-wavelength reflection filters have been fabricated by codeposition of SiO(2) and TiO(2). Composition modulation was monitored and controlled using quartz crystal rate controllers. The resulting filters exhibited two well-defined stopbands. Microscopic examination revealed that the structure is glasslike without pronounced thin film microstructure.

A method for depositing patterned infrared thin film spectral filters directly onto substrates at low temperatures (200 degrees C) is described. Energetic deposition methods (ion-assisted and laser-assisted) were used to avoid heating the substrates, while a multilayer photoresist lift-off technique was applied to pattern the structures. The process produced durable films capable of surviving harsh processing conditions. This is a promising method for depositing patterned coatings directly onto infrared focal plane detector arrays.