Interferometer spectrometer with reduced alignment sensitivity

A method of generating an optical interference pattern utilizing an interferometer having a plurality of optical components, the method comprising the steps of:

• generating an input ray;
• splitting the input ray into a first ray and a second ray, both the first ray and the second ray optically interacting with all of the optical components of the interferometer;
• creating an optical path length difference between the first and second rays;
• and
• combining the first ray and the second ray to form an output ray pair having an interference pattern.

An interferometer spectrometer, comprising:

• a beam splitter for splitting an input ray into a first ray and a second ray having a first path and a second path, the beam splitter having flat and parallel leading and trailing surfaces with homogenous refractive material disposed therebetween;
• a flat end mirror terminating the first path and the second path to define a first path length and a second path length, respectively, wherein the end mirror reflects the first and second rays back to the beam splitter to combine the rays into an output ray pair, wherein the rays forming the output ray pair are parallel;
• a compensator disposed between the beam splitter and the end mirror for equalizing the optical path lengths of the first and second paths, the compensator having flat and parallel leading and trailing surfaces with homogenous refractive material disposed therebetween;
• and
• a means for generating a difference between the first and second path lengths to create an interference pattern in the output ray pair.

An interferometer spectrometer, comprising:

• a beam splitter for splitting an input ray into a first ray and a second ray having a first path and a second path, the beam splitter comprising a plate having flat and parallel surfaces;
• a flat end mirror terminating the first path and the second path to define a first path length and a second path length, respectively, wherein the end mirror reflects the first and second rays back to the beam splitter to combine the rays into an output ray pair, wherein the rays forming the output ray pair are parallel;
• a compensator disposed between the beam splitter and the end mirror for equalizing the optical path lengths of the first and second paths, the compensator comprising a plate having flat and parallel surfaces;
• and
• a means for generating a difference between the first and second path lengths to create an interference pattern in the output ray pair;
• wherein translational changes in relative position between the beam splitter, the compensator and the end mirror do not result in a lack of parallelism or a lateral separation between the rays forming the output ray pair.

An interferometer spectrometer, comprising:

• a beam splitter for splitting an input ray into a first ray and a second ray having a first path and a second path, respectively;
• an end mirror terminating the first path and the second path to define a first path length and a second path length, respectively, wherein the end mirror reflects the first and second rays back to the beam splitter along the first and second paths, respectively, to combine the rays into an output ray pair;
• a compensator disposed between the beam splitter and the end mirror for equalizing the optical path lengths of the first and second paths;
• and
• a means for generating a difference between the first and second path lengths to create an interference pattern in the output ray pair, the path length difference generating means disposed in the first and second paths such that the first and second rays pass therethrough.

An interferometer spectrometer, comprising:

• a beam splitter comprising a block of refractive material having parallel first and second surfaces, the second surface having a partially reflective material thereon for splitting an input ray into a first ray and a second ray having a first path and a second path, respectively, the first surface having a reflective material thereon for reflecting the first ray such that the first and second rays exit the beam splitter in parallel;
• an end mirror terminating the first path and the second path to define a first path length and a second path length, respectively, wherein the end mirror reflects the first and second rays back to the beam splitter along the first and second paths, respectively, to combine the rays into an output ray pair;
• a compensator comprising a plate of refractive material having parallel sides, the compensator disposed between the beam splitter and the end mirror for equalizing the optical path lengths of the first and second paths;
• and
• a means for generating a difference between the first and second path lengths to create an interference pattern in the output ray pair.

An interferometer spectrometer, comprising:

• a beam splitter comprising a plate of refractive material having parallel leading and trailing surfaces, the trailing surface having a partially reflective material thereon for splitting an input ray into a first ray and a second ray having a first path and a second path, respectively, the leading surface having a reflective material thereon for reflecting the first ray such that the first and second rays exit the beam splitter in parallel;
• an end mirror terminating the first path and the second path to define a first path length and a second path length, respectively, wherein the end mirror reflects the first and second rays back to the beam splitter along the first and second paths, respectively, to combine the rays into an output ray pair;
• a compensator plate of refractive material having parallel sides for equalizing the amount of refractive material in the first and second paths, the compensator plate disposed between the beam splitter and the end mirror;
• an intersection mirror for causing the first and second paths to intersect at an intersection point, the intersection mirror disposed between the compensator and the end mirror;
• and
• a scanner plate of refractive material having parallel sides for generating a difference between the first and second path lengths to create an interference pattern in the output ray pair, the scanner plate disposed at the intersection point.

An interferometer spectrometer, comprising:

• a light source including an array of collimator lenses defining an elliptical angular subtense;
• a beam splitter for splitting the input ray into a first ray and a second ray having a first path and a second path, respectively;
• an end mirror terminating the first and second paths to define a first path length and a second path length, respectively;
• a compensator disposed between the beam splitter and the end mirror for equalizing the optical path lengths of the first and second paths;
• and
• a means for generating a difference between the first and second path lengths.