| Summary: | 博士 === 國立交通大學 === 光電工程研究所 === 86 === The principles, applications, and merits of the common-path
heterodyneinterferometer are described in this dissertation. To
investigate thisinterferometer, a new type of heterodyne light
source is designed firstly. Then,two new techniques for
measuring several physical quantities are proposed.
According to the physical quantities to be measured, and the
characteristics of the test medium, this interferometer can be
arranged intohree different types : transmission type, total-
internal-reflection type, and reflection type. As for the
transmission type, two lasers with different wavelengths andthe
heterodyne interferometry are used to determine the phase
retardation of a wave plate, and to locate its fast axis or slow
axis, simultaneously. As for the total-internal-reflection
(TIR) type, the total-internal-reflection heterodyne
interferometry is presented to measure the quantities,such as,
refractive index of liquid or gas, the absolute value of small
angle, and vacuum pressure. This new method is based on the
total-internal-reflectioneffect and the heterodyne
interferometry to measure the phase difference between s-
polarization and p-polarization due to TIR effect. The quantity
to be measured will be derived by submitting the corresponding
phase difference to Fresnel*s equations. As for the
reflection type, the phase difference versus incident
anglemethod for measuring the complex refractive index of a
medium is proposed. In this new method, the complex refractive
index can be derived by introducing the corresponding phase
differences between s- and p-polarizations of two different
incident angles into Fresnel*s equation. And the comparisons
between these methods and other traditional methods are
described. Because of its common-path optical configuration
and heterodyne interferometric phase evaluation, it has both the
merits of conventionalcommon-path interferometer and the
heterodyne interferometric technique. Hence it is suitable for
applying this interferometer to industry.
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