A free-space Michelson Interferometer-based Dual Detection Frequency Domain-Optical Coherency Tomography (DD-FD-OCT) apparatus includes a non-polarizing beam splitter that can be used to misalign sample and reference beam paths to provide a stable π/2 phase shift between simultaneously detected interfering sample and reference beams to eliminate the mirror image created by Fourier transformation during image reconstruction. A hybrid fiber system Mach Zehnder Interferometer- and free-space Michelson Interferometer-based Dual Detection Frequency Domain-Doppler Optical Coherency Tomography (DD-FD-DOCT) apparatus provides higher power efficiency and thus better sensitivity compared to the free-space DD-FD-OCT. Both DD-FD-OCT systems enable functional imaging with the contrasts of Doppler and that of polarization, in addition to full range images simultaneously.
Optical coherence tomography (OCT) apparatus, methods, and applications