A new method of generating the Bessel functions and ratios of Bessel functions necessary for Mie calculations is presented. Accuracy is improved while eliminating the need for extended precision word lengths or large storage capability. The algorithm uses a new technique of evaluating continued fractions that starts at the beginning rather than the tail and has a built-in error check. The continued fraction representations for both spherical Bessel functions and ratios of Bessel functions of consecutive order are presented.

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A single bubble of air in water can emit pulses of blue-white light that have durations of less than 50 ps while it is oscillating in an acoustic standing wave. The emission is called sonoluminescence. A knowledge of the bubble diameter throughout the cycle, and in particular near the time of sonoluminescence emission, can provide important information about the phenomenon. A new Mie scattering technique is developed to determine the size of the bubble through its expansion and collapse during the acoustic cycle. The technique does not rely on an independent means of calibration or on accurate measurements of the scattered intensity.

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Shore-based polarized infrared images ofship target and background were obtained in the MAPTIP measurement series, using vertical and horizontal polarization filters. These images have been analyzed to yield degree ofpolarization and polarization contrast enhancement for targets with sea and sky background. Strong vertical polarization is observed in the sea surface emission near the Brewster Angle in the 8-12 micrometer (LWIR) band, whereas horizontal polarization due to reflection is usually dominant in the 3-5 micrometer (MWIR) band. Ship targets at broadside aspect show a degree of polarization less than 5%. An enhancement of contrast by up to 30% in the LWIR (less in the MWTR) is obtained by polarization suppression of sea background. The contrast enhancement in the MWIR is counteracted by the horizontal polarization of reflected sunlight.

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An efficient new method of calculating spherical Bessel functions of complex argument based on continued fractions is developed. The method does not depend on recurrence relations and it a~lows accurate calculations on computers with differing word lengths. The method ma~ be easily extended to other types of Bessel functions and to complex orders.