Related Experiment Video
Updated: Jun 16, 2026

Quantitative Optical Microscopy: Measurement of Cellular Biophysical Features with a Standard Optical Microscope
Published on: April 7, 2014
Radial distribution of the refractive index in light-focusing rods: determination using Interphako interference
Abstract:
An interferometric technique for the determination of the radial distribution of the refractive index in lightfocusing plastic rods (LFR) has been developed using the shearing method of Interphako interference microscopy. We have derived mathematical expressions for the shape of interference fringes across the rod assuming the index distribution of LFR is described by n(r) n(=) (1 - ar(2) + br(4) + cr(6) + dr(2)) in which a, b, c, and d are distribution constants. The dsitribution constants were determined using a least-squares technique on a computer from the actual shape of fringes. Results for the representative cases are shown.
Related Concept Videos
Phase Contrast and Differential Interference Contrast Microscopy
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
Law of Rational Indices

