lorenzmie

IDL routines for analyzing in-line holographic microscopy images using the Lorenz-Mie theory of light scattering.

IDL is the Interactive Data Language, and is a product of Exelis Visual Information Solutions

lorenzmie is licensed under the GPLv3.

What it does

lorenzmie is intended for computing and analyzing holographic images of micrometer-scale spheres. It assumes that the illuminating laser beam is collimated along the optical axis and that the light is monochromatic, coherent, and uniformly polarized along the x (horizontal) axis. A sphere is specified by its three dimensional position, its radius and its complex refractive index. Spheres are assumed to have isotropic and linear optical properties. They may be radially stratified with layers defined by their radii and refractive indexes. The surrounding medium is characterized by its complex refractive index, and is assumed to be isotropic and homogeneous.

The code is organized from the most general components to the most specialized:

• sphericalfield: Calculates the complex electric field at a displacement (x,y,z) relative to the center of an illuminated object whose scattering properties are defined by Lorenz-Mie scattering coefficients.

• gpu_sphericalfield: A hardware-accelerated implementation of sphericalfield based on the GPULib library of IDL bindings to CUDA.

• sphere_coefficients: Calculates the Lorenz-Mie scattering coefficients for a multilayered sphere of radius ap and refractive index np immersed in a medium of refractive index nm at vacuum wavelength lambda. These coefficients then can be used in sphericalfield to compute the field scattered by a stratified sphere.

• spherefield: Uses sphere_coefficients and either sphericalfield or gpu_sphericalfield to compute the field scattered by a stratified sphere.

• lmsphere/: Computes normalized holograms of spheres based on the field computed by spherefield. Also fits experimentally measured holograms of colloidal spheres to the predictions of Lorenz-Mie theory.

References

1. S.-H. Lee, Y. Roichman, G.-R. Yi, S.-H. Kim, S.-M. Yang, A. van Blaaderen, P. van Oostrum and D. G. Grier, "Characterizing and tracking single colloidal particles with video holographic microscopy," Optics Express 15, 18275-18282 (2007).

2. F. C. Cheong, B. Sun, R. Dreyfus, J. Amato-Grill, K. Xiao, L. Dixon and D. G. Grier, "Flow visualization and flow cytometry with holographic video microscopy," Optics Express 17 13071-13079 (2009).

3. F. C. Cheong, B. J. Krishnatreya and D. G. Grier, "Strategies for three-dimensional particle tracking with holographic video microscopy," Optics Express 18, 13563-13573 (2010).

4. H. Moyses, B. J. Krishnatreya and D. G. Grier, Optics Express 21 5968-5973 (2013).

5. C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles (New York, Wiley 1983).

6. W. Yang, "Improved recurstive algorithm for light scattering by a multilayered sphere," Applied Optics 42, 1710--1720 (2003).

7. O. Pena and U. Pal, "Scattering of electromagnetic radiation by a multilayered sphere," Computer Physics Communications 180, 2348-2354 (2009).

8. P. Messmer, P. J. Mullowney and B. E. Granger, "GPULib: GPU computing in high-level languages," Computer Science and Engineering 10, 70-73 (2008)