Performing selected optical measurements with optical coherence domain reflectometry

A method for performing selected optical measurements on a sample according to this invention comprises:

• a. producing a beam of broad band light,
• b. splitting said beam of light into a signal beam and a reference beam,
• c. providing a reference mirror along the path of the reference beam,
• d. bringing the signal beam to focus on said sample,
• e. positioning a diffraction grating to receive reflections from the sample and from the reference mirror, the reflections being incident on the diffraction grating with respect to said diffraction grating normal such that a positive diffraction order from one of said reflections and a negative diffraction order form the other one of said reflections propagate along a normal to said diffraction grating, the two diffraction orders being the same number,
• f. providing a detector,
• g. collecting the diffracted orders from said diffraction grating propagating along said normal and bringing said diffracted orders collected to focus on said detector, said detector producing an output of said positive and negative diffracted orders received, and
• h. processing said output from said detector.

A system for performing selected optical measurements on a sample comprising:

• a. a light source,
• b. a first beamsplitter for splitting light from said light source into a signal beam and a reference beam,
• c. a reference mirror disposed along the path of the reference beam,
• d. the sample being disposed along the path of the signal beam,
• e. a first lens for bringing the signal beam to focus on said sample,
• f. a diffraction grating for receiving reflections from the sample and from the reference mirror and producing therefrom a diffracted beam, the reflections from the sample and the reference mirror being incident on the diffraction grating such that a positive diffraction order from the reflections from one of the samples and reference mirror and a negative diffraction order from the reflections from the other one of the samples and reference mirror are directed along the same path,
• g. a detector,
• h. a second lens for bringing said positive diffraction order and said negative diffraction order which are directed along said same path to focus on said detector, said detector producing an output of said positive diffraction order and said negative diffraction order received, and
• i. a computer for processing said output form said detector.

A method for performing selected optical measurements on a sample comprising:

• a. providing a light source,
• b. splitting light from said light source into a signal beam and a reference beam,
• c. positioning a reference mirror along the path of the reference beam,
• d. positioning the sample along the path of the signal beam,
• e. bringing the signal beam to focus on said sample,
• f. positioning a diffraction grating for receiving reflections from the sample and from the reference mirror and producing therefrom a diffracted beam, the reflections from the sample and the reference mirror being incident on the diffraction grating such that a positive diffraction order from the reflections from one of the sample and reference mirror and a negative diffraction order from the reflections from the other one of the sample and reference mirror are directed along the same path,
• g. providing a detector,
• h. bringing said positive diffraction order and said negative diffraction order directed along said same path to focus on said detector, said detector producing an output of said positive diffraction order and said negative diffraction order received, and
• i. processing said output from said detector.

A system for performing selected optical measurements on a sample comprising:

• a light source,
• b. a first beamsplitter for splitting light from said light source into a signal beam and a reference beam,
• c. a reference mirror disposed along the path of the reference beam,
• d. the sample being disposed along the paht of the signal beam,
• e. a first lens for bringing the signal beam to focus on said sample,
• f. a diffraction grating for receiving reflections from the reference mirror and producing therefrom a diffracted beam, the reflections from the reference mirror being incident on the diffraction grating such that a diffraction order from the reflections from the reference mirror is directed along a first path,
• g. a detector,
• h. a second beam-splitter for combing reflections from the sample with the diffraction order along said first path to produce a combined, beam,
• i. a second lens for bringing said combined beam to focus on said detector, said detector producing an output of said combined beam received, and
• j. a computer for processing said output from said detector.