Dispersion Staining

Dispersion Staining, Becke' Line

Becke' Line Dispersion Staining was first documented in 1911 by F. E. Wright in Publication #158 by the Carnegie Institute. He noted that when a particle and a liquid matched refractive indices for some wavelength in the visible range but they had different dispersion curves then two Becke' lines would be formed on defocusing the particle. The Becke' line for the blue end of the spectrum would move into the material with the steepest dispersion curve and the Becke'line for the red end of the spectrum would move into the material with the flatest dispersion curve.

The first two images below show a refractive index match at 589 nanometers wavelength

Glass Sphere in Matching Liquid

Glass Sphere in Matching Liquid

Dispersion Staining, Becke' Line

Test with Interference Filters

Dispersion Staining, Becke' Line

Dispersion Staining, Becke' Line

Dispersion Staining, Becke' Line

Oblique Dispersion Staining

Match at 590 nanometers wavelength

dsBLP1.66M7-1.662

dsBLN1.66M7-1.662

Match at 530 nanometers wavelength

dsBLP1.61M7-1.605

dsBLN1.61M7-1.605

Match at 550 nanometers wavelength

dsBL1.67M7-1.662

dsBL10XP1.67M7-1.662

dsBLN1.67M7-1.662

dsBL10XN1.67M7-1.662

Match at 460 nanometers wavelength

dsBLP1.68M7-1.662

dsBLN1.68M7-1.662