Refractive index dispersion functions of solid-phase polymers by multicolor optical diffraction

Journal Article · Mon Oct 16 04:00:00 EDT 2000 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.1318940· OSTI ID:40205298

Ford, J V; Sumpter, B G; Noid, D W; Barnes, M D; Otaigbe, J U

We show that fourth-order dispersion functions of solid-phase polymers can be determined by multicolor optical diffraction. Electrodynamically trapped microparticles of polyethylene glycol with different molecular weights were probed by two-dimensional optical diffraction with four different laser wavelengths (632.8, 514.5, 488.0, and 457.9 nm); subsequent Mie analysis of one-dimensional scattering patterns yielded size and refractive index (both real and imaginary parts). Using a single wavelength as a size reference, the nonlinear dependence of the refractive index of solid (nonevaporating) polymer microparticles was determined by finding the refractive index for a given wavelength that best matched a Mie calculation subject to the reference size constraint. The experimentally determined refractive index values were fit to a standard fourth-order Cauchy function to obtain values for n{sub 0}, n{sub 1}, and n{sub 2}.

• Sponsoring Organization: (US)
• OSTI ID: 40205298
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 16 Vol. 77; ISSN 0003-6951
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DIFFRACTION
LASERS
MOLECULAR WEIGHT
PHYSICS
POLYETHYLENE GLYCOLS
POLYMERS
REFRACTIVE INDEX
SCATTERING
WAVELENGTHS