Patent ID: 7116429

Claim:
An apparatus for measuring the thickness of slabs of materials comprising: a low coherence fiber optic interferometer comprised of a low coherence light source in optical communication with a first end of a single mode optical 2×2 fiber optic coupler and a light detector in optical communication with a second end of the single mode optical 2×2 fiber optic coupler, a reference arm comprising a single mode optical fiber in optical communication with a polarization controller connected to a first beam shaping lens system directing light upon a reflective element, and a delay stage comprising the reflective element attached to an electromechanical actuator, varying the length of the optical path between the first beam shaping lens system and the reflective element, a signal arm comprising single mode optical fiber connected to a second beam shaping lens system directing light upon a sample, a sample stage supporting and positioning the sample in front of the second beam shaping lens system, signal conditioning electronics connected to the light detector, a digital to analog converter electrically connected to the signal conditioning electronics, an electronic device monitoring the position of the delay stage optically connected to the delay stage, and a computer, electrically connected to the digital to analog converter, and the electronic device monitoring the position of the delay stage, acquiring and analyzing measured interferograms.