The refractive index of particulate matter suspended in seawater is nonuniform and potentially is an indicator of composition and origin. A method is described for determining the refractive index distribution. The method requires the measurement of the volume scattering function and assumes the total size distribution to be capable of being reproduced as a linear superposition of hyperbolic size distributions. The procedure utilizes 40 theoretical volume scattering functions computed for a range of refractive indices and particle size distributions. Each one represents a particular combination of index and distribution. The eight values for the refractive index (relative to that of water) range from 1.02 to 1.15. The distribution of refractive index and the total particle size distribution are determined by finding the best possible representation of the measured volume scattering function as a linear superposition of the 40 computed functions. An iterative descent method is used to minimize the error between the measured curve and the superposition of component scattering functions. If the particle size distribution is known beforehand, the determination can be restricted to reproduce the measured distribution to within limits set by a weighting factor. A similar technique is given for finding the refractive index composition for phytoplankton populations using measured scattering and size-distribution data. Twelve volume scattering functions measured in oceanic environments (Sargasso Sea, Mediterranean Sea and Baltic Sea) and three measured in cultured phytoplankton populations (the dinoflaggelate Amphidinium carterae, and unidentified unicellular alga labeled T-24, and a centric diatom of the genus Biddulphia) were analyzed. Determinations for the Mediterranean Sea were performed at a series of depths extending from near surface to 2OO m. All the determinations showed the refractive index distributions to be essentially bimodal with components of refractive indices near 1.05 and 1.15. The method reproduced measured scattering curves with an average absolute error less than the experimental uncertainty. Suggestions for obtaining better results using the same technique are given. / Graduation date: 1975

Thesis (Ph. D.)--Johns Hopkins University, 1916. / Reprinted from the Astrophysical journal, vol. XLV, no. 3, April, 1917.

Thesis (Ph. D.)--University of Michigan, 1907. / "Reprinted from the Physical Review, n.s., vol. I., no. 3, March, 1913."

Thesis (Ph. D.)--University of Michigan, 1907. / "Reprinted from the Physical Review, n.s., vol. I., no. 3, March, 1913."

Thesis (PH. D.)--Johns Hopkins university, 1916. / Reprinted from the Astrophysical journal, vol. XLV, no. 3, April, 1917.

Thesis (Ph. D.)--University of Chicago. / "Reprinted from the Physical review, Vol. XIV, No. 1, January, 1902." Includes bibliographical references. Also available on the Internet.

No description available.

Long period gratings (LPGs) are formed by inducing a permanent periodic modulation of the refractive index (RI) of the core of an optical fibre. The transmission spectrum of the LPG contains a series of attenuation bands centered at discrete wavelengths. The exact form of the transmission spectrum and the central wavelengths of the attenuation bands, are sensitive to the period and the length of the LPG and to the local environment. The sensitivity of a LPG to a particular measurand is dependant upon the composition of the fibre and upon the order of the cladding mode to which the guided mode is coupled to and is thus different for each attenuation band.

Abtract In this thesis, our purpose is to improve the refractive index models for direct-gap semiconductors. For refractive index spectrum of direct-gap compound semiconductors, most experimental data is available only bellow the bandgap absorption edge. For used in the optimum design of eltro-optic devices, such as waveguide, electro-absorption modulator and Mach-Zehnder interferometer. We have to utilize a little experimental data to extend refractive index spectrum to near and just above the band-gap edge. We have known that square of refractive index ( ) is dielectric constant ( ), so we decompose the dielectric constant ( ) into the part of band-to-band absorption and another part of single-oscillator high energy absorption. For the part of band-to-band absorption, we added broadening parameter ( ) and used Kramers-Kronig relation to transform the absorption coefficient into dielectric constant. For another part of single-oscillator high energy background absorption, we first cut the absorption part form experimental data and then use Sellmeier¡¦s equation to fit the residue data. Finally, recombine all equations and extend refractive index spectrum to near and just above the band-gap edge. We successfully built whole model and confirm our model with GaAs. The calculation result on GaAs shows an excellent agreement with the reported experimental data. Furthermore, We apply our model to direct-gap binary¡Bternary and quaternary compounded materials and extend our model to near and just above the band-gap edge very well.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.