AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Determination of Complex Refractive Index For Submicron Absorbing Spheres
JEONGHOON LEE, Korea University of Technology and Education
Abstract Number: 669 Working Group: Instrumentation and Methods
Abstract Real part and imaginary part of refractive index for absorbing spheres were determined using a multiangle absorption photometer together with Mie theory. For the absorbing spheres generated using a constant output atomizer, absorption coefficient was measured with a multiangle absorption photometer and number concentration was measured with a condensation particle counter. The absorption cross sections estimated from the absorption coefficients and particle number concentrations were fitted to the absorption cross sections calculated from the Mie theory. For the nigrosin, the refractive index obtained by the best fit corresponded to the 1.70 + 0.24i, which was obtained by minimizing the chi-square of the data. The refractive index measured by our method holds valid as long as the absorption phenomenon takes place in the near field surrounding particles surface. This method was applied to the measurement of the optical properties for non-homogeneously dyed absorbing particles. It was observed that the larger particle was less black than the smaller one. In this case, the absorption cross section was independent on the particle size. Furthermore, the refractive index for the non-homogeneous absorbing particles was investigated from the refractive index point of view.