Uranium oxide and uranium nitride thin films reflect significantly more than all previously known/standard reflectors (e.g., nickel, gold, and iridium) for most of the 4-10 nm range at low angles of incidence. This work includes measurements of the EUV/soft x-ray (2-20 nm) reflectance of uranium-based thin films (~20 nm thick) and extraction of their optical constants (d and ß). We report the reflectances at 5, 10, and 15 degrees grazing incidence of air-oxidized sputtered uranium, reactively sputtered (O 2 ) uranium oxide, and reactively sputtered (N 2 ) uranium nitride thin films measured at Beamline 6.3.2 at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL). Additionally, we report optical constants of reactively sputtered uranium oxide at nine wavelengths from 4.6 to 17.5 nm derived from ALS angle-scan reflectance measurements. We also report optical constants of uranium nitride at 13 and 14 nm. We compare the reflectance of these uraniumcompound thin films to gold, nickel (and nickel oxide), and iridium thin films from 2.5 to 11.6 nm. These metal thin films were chosen for comparison due to their wide use in EUV/soft x-ray applications as low-angle, thinfilm reflectors. The uranium compounds can exhibit some surface oxidation in ambient air. There are important discrepancies between UO 2 's and UN's actual thin-film reflectance with those predicted from tabulated optical constants of the elemental constituents of the compounds. These differences are also demonstrated in the optical constants we report. Uranium-based optics applications have important advantages for zone plates, thin-film reflectors, and filters.
The nonlinear optical properties of thin (1 mm) lithium niobate integrated optical substrates and much thicker (-8cm) boules can be obtained from the interference between the free and bound second harmonic waves (Maker fringes). The harmonic power is affected by the homogeneity of the plate, and this provides us with a method of quality control. We use a Q switched Nd:YAG laser to generate the harmonic power and the equipment is computer controlled. Fringe patterns that deviate appreciably from those expected for homogeneous plates indicate substrates that may not function properly in devices. In addition, the method can be used to analyze lithium niobate boules to ascertain if they are potentially useful for substrates.
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