Method and apparatus for holographic testing of optical components

A method for determining dimensional differences between two objects having complementary shapes comprising the steps of:

• constructing a hologram of one of the objects using radiant energy of predetermined temporal and spatial coherence;
• reconstructing said hologram using radiant energy substantially identical to that used in constructing said hologram, said hologram operating to attenuate the intensity of radiant energy incident thereto while transmitting the wavefront thereof undisturbed and additionally operating to diffract said radiant energy into ordered wavefronts comprising a plus one order wavefront that is identical to the wavefront which would be formed by reflecting from said one object the same kind of radiant energy used to construct said hologram and a minus one order wavefront that is the conjugate of said plus one order wavefront;
• forming a wavefront from the other object by directing thereat radiant energy substantially identical to that used to either construct or reconstruct said hologram and combining said other object wavefront with said minus one order wavefront from said hologram to form a viewable interference pattern;
• and
• interpreting said interference pattern to determine the dimensional differences between said objects.

A method for determining any dimensional differences between the shapes of objects intended to be complementary configured comprising the steps of:

• constructing a hologram of one of the objects using radiant energy of predetermined temporal and spatial coherence;
• reconstructing said hologram by directing thereat radiant energy substantially identical to that used to construct said hologram, said hologram operating to attenuate the intensity of said radiant energy directed thereat while transmitting the shape of the wavefront thereof undisturbed and to diffract said radiant energy directed thereat into ordered wavefronts comprising a plus-one order wavefront that is identical in shape to the wavefront which would be formed by said one object itself and a minus-one order wavefront that is identical in shape to the wavefront from an object having a shape that is precisely complementary to said one object;
• forming a wavefront from the other complementary configured object by directing thereat radiant energy substantially identical to that used in constructing or reconstructing said hologram;
• directing said other object wavefront onto said hologram to reconstruct said hologram a second time, said hologram operating to attenuate said other object wavefront while transmitting its shape undisturbed and to diffract said other object wavefront into ordered wavefronts comprising a minus-one wavefront which represents a combination of said other object wavefront and a wavefront from an object perfectly complementary in shape to said one object and a plus-one ordered wavefront which represents a combination of said other wavefront and a wavefront from said one object;
• combining said attenuated, undisturbed wavefront from said first reconstruction of said hologram with said plus-one ordered wavefront from said second hologram reconstruction to form a viewable interference pattern which represents an interference of said other object wavefront and a wavefront from its perfect complementary shape;
• and
• interpreting said interference pattern to determine the dimensional differences between the shapes of said objects.

Apparatus for determining any dimensional differences between the shapes of objects intended to be complementary configured, said apparatus comprising:

• a hologram of one of the complementary configured objects, said hologram being constructed using radiant energy of predetermined temporal and spatial coherence;
• means for mounting said hologram;
• a source for providing radiant energy having substantially the same properties as that used to construct said hologram;
• means for supporting the other object and said source in a predetermined manner;
• means for reconstructing said hologram using at least a portion of said source radiant energy, said hologram operating to diffract said radiant energy incident thereto into n-number of wavefronts where -a<n<+a and a is an integer;
• for forming a wavefront from said other object by directing thereat at least a portion of said source radiant energy;
• for directing said other object wavefront onto said hologram to reconstruct said hologram again, said hologram operating to diffract said other object wavefront into n-number of wavefronts where -a<n<+a and a is an integer, and for combining a predetermined n.sup.th -order wavefront from said first hologram reconstruction with the (n+1).sup.th -order wavefront from said other hologram reconstruction to form an interference pattern;
• and
• means for viewing said interference pattern so that said interference pattern can be interpreted to determine any dimensional differences between said objects.

Apparatus for determining any dimensional differences between the shapes of objects intended to be complementary configured, said apparatus comprising:

• a hologram of one of the complementary configured objects, said hologram being constructed using radiant energy of predetermined temporal and spatial coherence;
• means for mounting said hologram;
• a source for providing radiant energy having substantially the same properties as that used to construct said hologram;
• means for supporting the other object and said source in a predetermined manner;
• means for reconstructing said hologram by directing thereat at least a portion of said source of radiation so that said hologram operates to attenuate the intensity of said source radiation while transmitting the wavefront thereof undistributed and additionally operates to diffract said portion of said source radiation into ordered wavefronts comprising a plus one order wavefront that is identical to the wavefront which would be formed from reflecting from said one object radiation of the same kind as that of said source of radiation and a minus one order wavefront which is identical to the wavefront which would be formed by reflecting from a perfectly complementary configured other part the same kind of radiation as that of said source, for forming a wavefront from said other object by directing thereat at least a portion of said source radiation, and for combining said other object wavefront with said minus one order wavefront from said hologram to form an interference pattern;
• and
• means for viewing said interference pattern so that said interference pattern can be interpreted to determine dimensional differences between said objects.

Apparatus for determining any dimensional differences between the shapes of objects intended to be complementary configured, said apparatus comprising:

• a hologram of one of the complementary configured objects, said hologram being constructed using radiant energy of predetermined temporal and spatial coherence;
• means for mounting said hologram;
• a source for providing radiant energy having substantially the same properties as that used to construct said hologram;
• means for supporting the other object and said source in a predetermined manner;
• means for reconstructing said hologram using at least a portion of said source radiant energy, said hologram operating to attenuate the intensity of radiant energy incident thereto while transmitting the wavefront thereof undisturbed and additionally operating to diffract said radiant energy into ordered wavefronts comprising a plus one order wavefront that is identical to the wavefront which would be formed by reflecting from said one object the same kind of radiant energy used to construct said hologram and a minus one order wavefront that is identical in shape to the wavefront formed by reflecting from a perfectly complementary configured other part radiation from said source, for forming a wavefront from said other object by directing thereat at least a portion of said source radiant energy, and then, for directing said other object wavefront at said hologram, said hologram further operating to attenuate said other object wavefront while transmitting its shape undisturbed and additionally operating to diffract said other object wavefront into ordered wavefronts comprising a minus one order wavefront which represents a combination of said other object wavefront and a wavefront from an object perfectly complementary in shape to said one object and a plus one order wavefront which represents a combination of said other object wavefront and a wavefront from said one object, and for combining said attenuated, undisturbed wavefront from said first reconstruction of said hologram with said plus one ordered wavefront generated by directing said other object wavefront at said hologram to form an interference pattern which represents an interference of said other object wavefront and a wavefront from its perfect complementary shape;
• and
• means for viewing said interference pattern so that said interference pattern can be interpreted to determine dimensional differences between said objects.

A method for determining any dimensional differences between the shapes of objects intended to be complementary configured comprising the steps of:

• constructing a hologram of one of the objects using radiant energy of predetermined temporal and spatial coherence;
• reconstructing said hologram using radiant energy substantially identical to that used to construct said hologram, said hologram operating to diffract said radiant energy incident thereto into n-number of wavefronts where -a<n<+a and a is an integer;
• forming a wavefront from the other object by directing thereat radiant energy substantially identical to that used to either construct or reconstruct said hologram;
• directing said other object wavefront onto said hologram to reconstruct said hologram again, said hologram operating to transmit the shape of said other object wavefront undisturbed and also to diffract said other object wavefront into n-number of wavefronts where -a<n<+a and a is an integer;
• combining a predetermined n.sup.th -order wavefront from said first hologram reconstruction with the corresponding (n+1).sup.th -order wavefront from said other hologram reconstruction to form an interference pattern;
• and
• interpreting said interference pattern to determine any dimensional differences between said objects.