An algorithm was developed to obtain depth-resolved local optical axis in birefringent samples by using conventional polarization-sensitive optical coherence tomography (PSOCT) that uses a single circularly polarized incident light. The round-trip sample Jones matrices were first constructed from the cumulative PSOCT results. An iterative method was then applied to construct the depth-resolved local Jones matrix from which the local optical axis was calculated. The proposed algorithm was validated in samples with homogeneous axis and with depth-varying optical axis. Imaging examples were shown to demonstrate the capability of this method for extracting correct local axis and revealing features not evident in other images.
A fast imaging system that can reveal internal sample structures is important for research and quality controls of seeds.
Optical coherence tomography (OCT) is a non-invasive optical imaging technique that can acquire high speed, high
resolution depth-resolved images in scattering samples. It has found numerous applications in studying various
biological tissues and other materials in vivo. A few studies have reported the use of OCT in studying seed morphology.
However, 3D imaging of internal seed structure has not been reported before. In this study, we used a frequency domain
OCT system to image tomato seeds. The system has a central wavelength of 844nm with a 46.8 nm FWHM bandwidth.
The requirement for depth scan was eliminated by using a Fourier domain implementation. The B-scan imaging speed
was limited by the spectroscopic imaging CCD at 52 kHz. The calibrated system has a 6.7μm depth resolution and a
15.4μm lateral resolution. Our results show that major seed structures can be clearly visualized in OCT images.
In this talk, a spectral domain polarization sensitive optical coherence tomography (SDPS-OCT) system has been developed so as to obtain high scan speed, high dynamic range and high sensitivity, and simultaneously get birefringence contrast of some biological tissue. To reduce corruption of the DC and autocorrelation terms to images, we introduce the two phase method. The stocks vectors (I, Q, U, and V) of the backscattered light from the specimen have been reconstructed by processing the signals from the two channels which are responsible for detecting the vertical and horizontal polarization state light separately. Further, the phase retardation between the two orthogonal polarization states has been acquired. The results from rabbit eye show that SDPS-OCT system based on the two phase method has great potential to imaging biological tissue.
A spectral domain Polarization sensitive optical coherence tomography (SDPS-OCT) system has been developed to acquire depth images of biological tissues such as porcine tendon, rabbit eye. The Stocks vectors (I, Q, U, and V) of the backscattered light from the biological tissues have been reconstructed. Further, the phase retardation and polarization degree between the two orthogonal polarizing states have been computed. Reconstructed images, i.e. birefringence images, from Stokes parameters, retardation and polarization degree of biological tissues show significant local variations in the polarization state. And the birefringence contrast of biological tissue possibly changes by some outside force. In addition, the local thickness of the birefringence layer determined with our system is significant. The results presented show SDPS-OCT is a potentially powerful technique to investigate tissue structural properties on the basis of the fact that any fibrous structure with biological tissues can influence the polarization state of light.