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Based on theoretical investigations of the light propagation within an integrating sphere, we developed an accurate method to determine the optical properties of scattering media using an integrating sphere-based setup. The method takes into account the exact sphere geometry as well as the different angular distributions of the reflected and transmitted light from the sample and the calibration standard. We tested our novelties successfully in theory with Monte Carlo simulations and in practice using a 3D printed and professionally coated integrating sphere. As a result, we were able to determine precisely the effective scattering coefficient, μ s ′ , and the absorption coefficient, μ a , between 400 nm and 1500 nm in a range of μ a = 1 e − 3 m m − 1 to 10 m m − 1 and μ s ′ = 0.2 m m − 1 to 100 m m − 1 . Usually, the accuracy was around 1% for μ s ′ and around 3% for μ a for turbid phantom media with an optical thickness τ = μ s ′ d > 1 and a transmittance signal > 0 . 1 % .

“Phase-Measuring Deflectometry” (PMD) has been developed at Erlangen to measure spatially resolved slope data of specular surfaces [1], [2] and [3]. The principle is simple: A camera observes the image of a sinusoidal grating via reflection at the surface under test. The local slope of the sample is encoded in the deformation of the observed pattern [4]. Meanwhile, PMD is well established to control the manufacturing of aspheric eyeglasses. PMD even has the potential to challenge interferometry. This specifically, because in contrast to interferometry, PMD does not display retrace errors. We will discuss the objectives and potentials of PMD on the road to sub-micrometer accuracy, as well as new applications including machine-integrated measurements.

When lead chloride is deposited onto substrates at temperatures below 150 K, a non-crystalline film is formed. This material crystallizes at temperatures above 260 K, as could be demonstrated by UV-VIS-spectroscopy. In order to determine whether or not the deposited material consists of extremely small crystals with a high degree of disorder or of a genuine amorphous phase, it was investigated by electron diffraction. We describe the procedure which we applied for the determination of the elastically scattered intensity as a function of the scattering vector. From this function, the reduced radial distribution function was determined. The results were compared with those reported about crystalline and molten lead chloride. The short range order in the cold condensed material is different from that in the crystal and that in the melt. Hence, cold condensation of lead chloride leads to the formation of an ionic glass.

By comparison of the UV spectra of freshly prepared cold condensed lead chloride films with those of tempered ones, it can be seen that initially non crystalline material is formed. The excitonic transitions give rise to broad structureless bands. Upon annealing, these bands shift and become more sharply. From the excitonic absorption at about 270 nm the non crystalline to crystalline transition can be monitored quantitatively. We can demonstrate that this is a first order phase transition. Nucleation is a necessary step. The initial non crystalline state therefore is metastable and not a frozen-in state.

By comparison of the UV spectra of freshly prepared cold condensed lead chloride films with those of tempered ones, it can be seen that initially non crystalline material is formed. The excitonic transitions give rise to broad structureless bands. Upon annealing, these bands shift and become more sharply. From the excitonic absorption at about 270 nm the non crystalline to crystalline transition can be monitored quantitatively. We can demonstrate that this is a first order phase transition. Nucleation is a necessary step. The initial non crystalline state therefore is metastable and not a frozen-in state.

UV/VIS spectroscopic studies with cold condensed silver chloride films are reported. During annealing of these films, an exciton band grows out of an initially contourless broad absorption edge. From the temperature dependence and from the time behavior of this absorption it is concluded, that the noncrystalline state of the chloride, which is formed during the condensation, is a metastable phase. The transition to the crystalline state is of an order > 1. A small red shift of the maximum of the exciton band during the transformation indicates that the crystalline nuclei grow during this process.