Laser interferometer

Claim 2

An interferometer comprising: a. a source of a primary beam of coherent light; b. means for dividing said primary light beam into a pair of secondary beams having characteristic Poincare sphere vectors; c. means for combining said secondary beams to form a composite beam having a resultant Poincare vector; d. means disposed in substantially the whole of the aperture of at least one of said primary, said secondary or said composite beams for orienting the Poincare vectors of the secondary beam components of said composite beam into antiparallel North-South disposition with reference to the Poincare sphere, thereby disposing said resultant Poincare vector in the equatorial plane of said sphere; e. means disposed in the paths of said secondary beams intermediate said dividing means and said combining means for creating a cycling difference between the phases of said secondary beams, whereby said resultant Poincare vector will describe a locus of orientation symmetrical about said antiparallel vectors; f. means for dividing said composite beam into a plurality of at least three tertiary beams, each of said tertiary beams comprising substantially the whole of the aperture of said composite beam; g. polarizing means disposed with respect to the whole of the apertures of each of said tertiary beams for modulating the intensity of each said beam according to the orientation of said resultant Poincare vector in said locus, said polarizing means being disposed with respect to each other so as to minimize the intensities of their respective tertiary beams at different orientations of said resultant Poincare vector; and h. means responsive to said modulation in the intensity of said tertiary beams to provide electrical signals corresponding to said intensity modulation.

Claim 3

An interferometer according to claim 1 wherein said primary light beam dividing means divides said primary beam into a pair of secondary beams having antiparallel Poincare sphere vectors.

Claim 4

An interferometer according to claim 2 wherein said means for orienting the Poincare sphere vectors of the secondary beam components of said composite beam into North-South disposition is disposed in substantially the whole of at least one of said primary beam, said composite beam, or said pair of secondary beams.

Claim 5

An interferometer according to claim 2 wherein said primary light beam is a laser beam, and said primary light beam dividing means comprises a polarizing beamsplitter so disposed in substantially the whole of the aperture of said primary beam and with respect to rotation about the axis of said primary beam as to divide said primary beam into a pair of secondary beams having said antiparallel Poincare vectors oriented in the equatorial plane of said Poincare sphere.

Claim 6

In an interferometer comprising a primary coherent light beam source, a polarizing beamsplitter for dividing a light beam from said source into first and second secondary component beams having antiparallel Poincare sphere vectors, means for varying the phase relationship between said first and second beams, means disposed respectively in said first and second beams for transposing the orientations of the Poincare vectors of said first and second beams, means for returning said first and second beams back to a common point on said beamsplitter, whereby said first and second beams which were initially respectively wholly passed and reflected by said beamsplitter are thereupon respectively wholly reflected and passed by said beamsplitter thereby forming a composite beam having a resultant Poincare vector, the orientation of said resultant vector being a function of said phase relationship between said first and second beams, the improvement which comprises means for distinguishing said resultant Poincare vector orientation, said distinguishing means comprising: a. means disposed in substantially the whole of the aperture of at least one of said primary, secondary or composite beams for orienting the antiparallel Poincare vectors of the first and second beam components of said composite beam into North-South disposition with reference to the Poincare sphere, thereby disposing said resultant Poincare vector in the equatorial plane of said sphere, said plane being coincident with the locus described by said resultant Poincare vector upon cycling variation in said phase relationship; b. means disposed in the path of said composite beam for dividing said composite beam into a plurality of at least three tertiary beams, each of said tertiary beams comprising substantially the whole of the aperture of said composite beam; c. polarizing means disposed with respect to the whole of the apertures of each of said tertiary beams for modulating the intensity of each said beam according to the orientation of said resultant Poincare vector in said locus, said polarizing means being disposed with respect to each other so as to minimize the intensities of their respective tertiary beams at different orientations of said resultant Poincare vector; and d. means responsive to said modulation in the intEnsity of said tertiary beams to provide electrical signals corresponding to said intensity modulation.

Claim 7

In an interferometer comprising a primary coherent light beam source, a polarizing beamsplitter for dividing a light beam from said source into first and second secondary component beams having antiparallel Poincare sphere vectors, means for varying the phase relationship between said first and second beams, means disposed respectively in said first and second beams for transposing the orientations of the Poincare vectors of said first and second beams, means for returning said first and second beams back to a common point on said beamsplitter, whereby said first and second beams which were initially respectively wholly passed and reflected by said beamsplitter are thereupon respectively wholly reflected and passed by said beamsplitter thereby forming a composite beam having a resultant Poincare vector, the orientation of said resultant vector being a function of said phase relationship between said first and second beams, the improvement which comprises means for distinguishing said resultant Poincare vector orientation, said distinguishing means comprising: a. means disposed in substantially the whole of the aperture of at least one of said primary, secondary or composite beams for orienting the antiparallel Poincare vectors of the first and second beam components of said composite beam into North-South disposition with reference to the Poincare sphere, thereby disposing said resultant Poincare vector in the equatorial plane of said sphere, said plane being coincident with the locus described by said resultant Poincare vector upon cycling variation in said phase relationship; b. means disposed in the path of said composite beam for dividing said composite beam into a plurality of at least three tertiary beams, each of said tertiary beams comprising substantially the whole of the aperture of said composite beam; c. polarizing means disposed with respect to the whole of the apertures of each of said tertiary beams for modulating the intensity of each said beam according to the orientation of said resultant Poincare vector in said locus, said polarizing means being disposed with respect to each other so as to minimize the intensities of their respective tertiary beams at different orientations of said resultant Poincare vector; and d. means responsive to said modulation in the intEnsity of said tertiary beams to provide electrical signals corresponding to said intensity modulation.

Claim 8

The improvement according to claim 5 including means for differencing at least two pairs of said electrical signals, thereby providing at least one pair of electrical signals, without DC components, useful as input signals for a reversible digital counter.

Claim 9

The improvement according to claim 5 wherein: a. said composite beam dividing means provides three tertiary beams; b. said polarizing means are so disposed with respect to each other as to provide minimized intensities of said tertiary beams at orientations of said resultant Poincare vector relatively disposed about said antiparallel vectors at azimuths of 0*, 90*, 180*, thereby providing intensity modulations varying in phase by increments of 90*; and c. means are provided for differencing those pairs of said electrical signals whose phases of modulation differ by 90*, thereby providing a pair of electrical signals, without DC components, useful as input signals for a reversible digital counter.

Claim 10

The improvement according to claim 5 wherein said composite beam dividing means comprises: a. a plurality of polarizing beamsplitters disposed in longitudinal array in substantially the whole of the path of said composite beam, said beamsplitters being so constructed as to substantially wholly transmit a beam of one Poincare vector orientation and reflect varying substantial portions of beams of other Poincare vector orientations, said plurality of beamsplitters being further variously disposed with respect to each other so as to wholly transmit beams of different ones of said Poincare vector orientations; and b. a separate photoelectric element disposed to receive light beams reflected from each of said plurality of beamsplitters, thereby providing a like plurality of separate detectable signals with respect to a plurality of resultant Poincare vector azimuths.

Claim 11

The improvement according to claim 8 wherein said orientation distinguishing means provides detectable signals with respect to resultant Poincare vector orientations relatively disposed at 0*, 90*, and 180* in the equatorial plane of the Poincare sphere. 10 The improvement according to claim 8 including means for differencing at least two pairs of said electrical signals, thereby providing at least one pair of electrical signals, without DC components, useful as input signals for a reversible digital counter.