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Measurements of the index of refraction of a sample of high-quality, single-crystal germanium using the minimum deviation refractometry method are presented for temperatures near 22°C and for wavelengths in the range 2 to 14 µm. The standard uncertainty for the measurements ranges from ${1.5} \times {{10}^{ - 5}}$1.5×10 -5 to ${4.2} \times {{10}^{ - 5}}$4.2×10 -5 , generally increasing with wavelength. A Sellmeier formula fitting the data for this range is provided. Details of the custom system and procedures are presented, along with a detailed analysis of the uncertainty. These results are compared with previous measurements.

Si:As blocked impurity band detectors have been partially deprocessed and measured by Fourier transform spectroscopy to determine their transmittance and reflectance at cryogenic temperatures over the wavelength range 2 μm to 40 μm. A method is presented by which the propagation constants can be extracted from an inversion of the transmittance and reflectance data. The effective propagation constants for the active layer from 2 μm to 20 μm were calculated as well as the absorption cross section of arsenic in silicon, which agrees well with previous results from the literature. The infrared absorptance of the full detector was determined, and the analytical method also provides an estimate of absorption in the active layer alone. Infrared absorptance of the active layer is compared to the quantum yield measured by photoelectric means on similar detectors. The optical methods outlined here, in conjunction with standard electronic measurements, could be used to predict the performance of such detectors from measurements of the blanket films from which they are to be fabricated., (© 2011 Optical Society of America)

We describe the design and performance of a liquid helium-cooled As:Si blocked-impurity-band photodetector system intended for spectrophotometry in the thermal infrared (2 to 30 mum) spectral region. The system has been characterized for spectral sensitivity, noise, thermal stability, and spatial uniformity, and optimized for use with a Fourier-transform infrared spectrophotometer source for absolute goniometric reflectance measurements. Its performance is evaluated and compared to more common detector systems used in this spectral region, including room-temperature pyroelectric and liquid-N(2)-cooled photoconductive devices.

We present measured values of the refractive index, thermo-optic coefficient, and absorption coefficient of a number of common organic solvents and aqueous inorganic solutions that may have application in immersion photolithography at 248 or 193 nm wavelengths. The measurements were performed with a laser-based Hilger-Chance refractometer system whose design and operation are described. The optical properties of the sample fluids are compared with those of water, the currently favored immersion medium, and we discuss the potential for finding higher-index fluids that will be suitable for this application.

We have designed and constructed a linear polarizer for use with visible and infrared radiation. The broadband polarizer consists of four germanium plates arranged in a chevron geometry. Input radiation is incident near Brewster's angle for the first plate such that the reflected beam is preferentially s-wave polarized. This reflected beam is steered subsequently to the successive plates, always intersecting near Brewster's angle. The beam polarization at the output of the device is almost completely s-wave polarized. The ratio of the paraxial flux of the nearly extinguished p-wave polarized light to the s-wave polarized light transmitted through the device is found to be less than 10(-5) for laser illumination at wavelengths of 0.633, 1.32, 3.39, and 10.6 mum. Calculations predict that extinction ratios less than 10(-5) are achievable over the wavelength range from 0.4 mum to beyond 500 mum. Alternative design geometries involving fewer plates are also described along with their advantages and disadvantages.

We have investigated the ordinate scale accuracy of ambient temperature transmittance measurements made with a Fourier transform infrared (FT-IR) spectrophotometer over the wavelength range of 2-10 mum. Two approaches are used: (1) measurements of Si wafers whose index of refraction are well known from 2 to 5 mum, in which case the FT-IR result is compared with calculated values; (2) comparison of FT-IR and laser transmittance measurements at 3.39 and 10.6 mum on nominally neutral-density filters that are free of etaloning effects. Various schemes are employed to estimate and reduce systematic error sources in both the FT-IR and laser measurements, and quantitative uncertainty analyses are performed.