User Guide

490 Series Microscope
AmScope Proprietary Page 25 of 64
As waves of light move
through space, if their cycles
move in a perfect parallel
and are at the same point in
their cycles, they are in-
phase.
If some of the light waves hit
an obstacle and the phases
of the waves are altered, so
they are no longer in parallel
and at the same point in
their cycles, they are out-of-
phase.
When a light wave passes
through any medium, the
medium can affect the light
wave’s length, amplitude,
frequency and phase. There
are shifts in phase, due to
changes in light’s speed.
As the speed of light changes when hitting or missing obstacles, like a specimen, the
rays are bent, or refracted. The amount of refraction when a light wave hits an obstacle
is measured as its refractive index. It’s this refractive index which creates the variations
in phase as light passes through a specimen.
Even though a specimen may appear transparent, as long as its refractive index is
different from the baseline index of air, and the specimen has thickness, then there will
be changes in phase to any light which passes through the specimen.