Patent ID: 6608717
Filing Date: 2003-08-19
Classification: A61B,G01B,G01N,G02B

Abstract:
A high resolution optical coherence microscope system for visualizing structures below a surface of a biological sample, the system comprising:a light source emitting light in a wavelength of between 700 and 1500 nm; a reference mirror; a focusing lens for focusing light on the biological sample; a photodetector; a sample optical path for receiving light from the light source and directing the light to the focusing lens, said sample path having a sample path length, wherein the light directed along the sample path enters the biological sample and tapers to a beam waist diameter within the sample; a reference optical path for receiving light from the light source and directing the light to the reference mirror, said reference path having a reference path length; a piezoelectric device, wherein the length of at least one of the optical paths is modulated by the piezoelectric device, and wherein a light beam from the sample optical path scattered back from the biological sample is combined with a light beam from the reference path reflected from the reference mirror, wherein the combination of light beams produces an interference fringe signal on the photodetector when the sample path length and the reference path length are substantially the same to within the coherence length of the light source, wherein an amplitude of modulation is less than 0.50 of the wavelength, and the powers in a fringe signal at a fundamental frequency, f, and a second harmonic of the fundamental frequency, 2f, are summed to provide a measure of the amplitude of the fringes; and a scanner arranged to scan the beam waist across a first plane substantially normal to the direction of the incident light beam, and to then move the beam waist deeper into the sample and to scan another plane while the position of the reference mirror is translated to keep the equal path lengths of the sample and reference paths coincident with the beam waist, and that the fringe amplitude is recorded at each volume element voxel during the scan of the sample resulting in a three-dimensional data set that is volume-rendered to provide a three-dimensional visualization of the sample.