PASCO OS-9257A PRECISION INTERFEROMETER - Manual (Page 5)

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012-07137A Precision Interferometer
Introduction
The OS-9255A Precision Interferometer provides both a
theoretical and a practical introduction to interferometry.
Precise measurements can be made in three modes:
Michelson
The Michelson Interferometer is historically important, and
also provides a simple interferometric configuration for
introducing basic principles. Students can measure the
wavelength of light and the indices of refraction of air and
other substances.
Twyman-Green
The Twyman-Green Interferometer is an important
contemporary tool for testing optical components. It has
made it possible to create optical systems that are accurate
to within a fraction of a wavelength.
➤ NOTE: The PASCO Precision Interferometer is
not designed for actual component testing in the
Twyman-Green mode. It is intended only to provide
a simple introduction to this important application of
interferometry.
Fabry-Perot
The Fabry-Perot Interferometer is also an important
contemporary tool, used most often for high resolution
spectrometry. The fringes are sharper, thinner, and more
widely spaced than the Michelson fringes, so small differ-
ences in wavelength can be accurately resolved. The
Fabry-Perot interferometer is also important in laser
theory, as it provides the resonant cavity in which light
amplification takes place.
Switching between these three modes of operation and
aligning components is relatively simple, since all mirrors
mount to the base in fixed positions, using captive panel
screws. Lenses, viewing screens, and other components
mount magnetically to the base using the included compo-
nent holders.
Measurements are precise in all three modes of operation.
A 5 kg machined aluminum base provides a stable surface
for experiments and measurements. All mirrors are flat to
1/4 wavelength, and the built-in micrometer resolves mirror
movement to within one micron.