US 6,208,415 B1 · Birefringence imaging in biological tissue using polarization sensitive optical coherent tomography

Abstract

Employing a low coherence Michelson interferometer, two dimensional images of optical birefringence in turbid samples as a function of depth are measured. Polarization sensitive detection of the signal formed by interference of backscattered light from the sample and a mirror or reference plane in the reference arm which defines a reference optical path length, give the optical phase delay between light propagating along the fast and slow axes of the birefringence sample. Images showing the change in birefringence in response to irradiation of the sample are produced as an example of the detection apparatus and methodology. The technique allow rapid, noncontact investigation of tissue or sample diagnostic imaging for various medical or materials procedures.

Claims33

Dependent claims

An apparatus for polarization sensitive optical coherence tomography of a sample characterized by optical birefringence comprising:

an interferometer having a source arm, a reference arm, a sample arm and a detector arm;
a source of at least partially coherent polarized light coupled to said source arm, said partially coherent polarized light being characterized by a well defined polarization state;
a polarization modulator, wherein polarization modulated light is returned to said detector arm from said reference arm and wherein polarization modulated light is incident on said sample and arbitrarily polarized light is returned to said detector arm from said sample arm according to sample birefringence, said returned light from said reference arm and sample arm interfering in said detector arm to form polarization interference fringes;
and
a polarization demodulator to demodulate said polarization interference fringes to generate a complete polarization state description of said backscattered light from said sample by preserving phase relationships between orthogonal components of said polarization interference fringes formed from backscattered light from said sample and from said reference arm.

2 more elements

A method for performing polarization sensitive optical coherence tomography of a sample characterized by optical birefringence comprising:

providing a source of at least partially coherent light coupled to an interferometer having a source arm, a reference arm, a sample arm and a detector arm;
polarization modulating said light in at least said reference arm or sample arm;
returning said polarization modulated partially coherent light to said detector arm from said reference arm and said sample arm, said polarization modulated partially coherent light being incident on said sample and arbitrarily polarized light being returned to said detector arm from said sample arm according to sample birefringence, said returned light from said reference arm and sample arm interfering in said detector arm to coherently gate said returned light from said sample arm in said detection arm to select between a multiplicity of optical paths of backscattered light returned from said sample arm to form polarization interference fringes;
and
demodulating said polarization interference fringes in said detector arm combined from light returned from said reference arm and from said sample arm to provide a data signal indicative said optical birefringence of said sample.

2 more elements

Dependencies are inferred from the claim text.

Birefringence imaging in biological tissue using polarization sensitive optical coherent tomography

Life of this patent

Birefringence imaging in biological tissue using polarization sensitive optical coherent tomography

Life of this patent

Abstract

Claims33