Refractive index dispersion functions of solid-phase polymers by multicolor optical diffraction
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, Vol. 77, Issue 16; Other Information: DOI: 10.1063/1.1318940; Othernumber: APPLAB000077000016002515000001; 041042APL; PBD: 16 Oct 2000; ISSN 0003-6951
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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