Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
A phase-determining interferometer for determining the phases at different points in the wavefront of an incoming test beam of light comprising: point diffraction interferometer (PDI) means for forming a directly transmitted and a diffracted beam whose polarization vectors are orthogonal to each other, said PDI means having a focusing means and a half-wave, partially transmitting plate with a pinhole therein, the diameter of the pinhole being small enough to form a spherical unaberrated reference wavefront from the light focussed on the pinhole; frequency-shifting means for converting said orthogonal beams from the interferometer into two beams differing in frequency from each other and forming a moving interference pattern therefrom in a plane transverse to the beam propagation axis; and means for converting the irradiance at specific points in the output beam pattern of the frequency-shifting means into proportionate phase-indicating data.
Claim 2
Dependent Claim
139 words
A phase-determining interferometer for determining the phases at different points in the wavefront of an incoming test beam of light comprising: point diffraction interferometer (PDI) means for forming a directly transmitted and a diffracted beam whose polarization vectors are orthogonal to each other, said PDI means having a focusing means and a half-wave, partially transmitting plate with a pinhole therein, the diameter of the pinhole being small enough to form a spherical unaberrated reference wavefront from the light focussed on the pinhole; frequency-shifting means for converting said orthogonal beams from the interferometer into two beams differing in frequency from each other and forming a moving interference pattern therefrom in a plane transverse to the beam propagation axis; and means for converting the irradiance at specific points in the output beam pattern of the frequency-shifting means into proportionate phase-indicating data.
Claim 3
Dependent Claim
42 words
An interferometer as in claim 1, wherein: said frequency-shifting means includes means for imposing a sinusoidal frequency of 2ω upon the two orthogonal beams received by the frequency-shifting means, whereby the frequencies of the two beams are displaced from their original frequency.
Claim 4
Dependent Claim
42 words
An interferometer as in claim 2, wherein: said frequency-shifting means includes means for shifting the polarization vectors of the two frequency-shifted beams so that both lie along the same axis in the same direction and the beams provide a moving interference pattern.
Claim 5
Dependent Claim
61 words
An interferometer as in claim 3, wherein: the irradiance in the output beam of the frequency-shifting means is given by I=1+A sin (4ωt+φ) where A is the amplitude of the sinusoidal part of the irradiance, ω is the imposed sinusoidal frequency and φ is the phase of the diffracted beam through the pinhole relative to that of the directly transmitted beam.
Claim 6
Dependent Claim
24 words
An interferometer as in claim 3, wherein: said means for imposing a sinusoidal frequency comprises a half-wave plate rotating at an angular frequency ω.
Claim 7
Dependent Claim
16 words
An interferometer as in claim 4, wherein: said converting means converts the irradiance into phase-difference data.
Claim 8
Dependent Claim
102 words
An interferometer as in claim 6, wherein: said converting means comprises a plurality of photodetectors, one being used as a reference photodetector and the rest as test photodetectors, the photodetectors being arranged in an array transversely to the beam direction so that each reads a different point in the transverse interference pattern presented by the output beam of the frequency-shifting means, and a plurality of phase-to-voltage converters, each receiving the output of the reference photodetector and the output of a different one of said test photodetectors and converting its inputs into an output proportional to the phase difference between the two inputs.