Full-range polarization-sensitive swept-source optical coherence tomography by simultaneous transversal and spectral modulation.
Polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) is used to measure three-dimensional phase-retardation images of birefringent biological tissue in vivo. PS-SS-OCT with continuous source polarization modulation is used to multiplex the incident states of polarization in the signal frequency of each A-scan. Although it offers the advantage of measurement speed that is as high as that of standard SS-OCT, its disadvantage is low axial measurement range. To overcome this drawback, we employed the B-M-mode scan (BM-scan) method, which removes complex conjugate ambiguity by applying phase modulation along the transversal scanning direction. Since polarization modulation and BM-scan are applied in different scanning directions, these methods can be combined to make the optimum use of both full range and polarization-sensitive imaging. Phase fluctuations that cause measurement failure were numerically canceled before demodulating the B-scan oriented modulation. After removing complex conjugate artifacts, the axial measurement range was 5.35 mm, and the signal-to-conjugate ratio was 40.5 dB. We demonstrated retinal imaging using the PS-SS-OCT system with a frequency-swept laser at a center wavelength of 1064 nm and an axial resolution of 11.4 microm in tissue. Full-range polarization-sensitive retinal images showed characteristic birefringence of fibrous tissues such as retinal nerve fiber, sclera, and lamina cribrosa.
Yamanari
Masahiro
M
Computational Optics Group in the University of Tsukuba, Tsukuba, Ibaraki, Japan. yamanari@optlab2.bk.tsukuba.ac.jp
Makita
Shuichi
S
Lim
Yiheng
Y
Yasuno
Yoshiaki
Y
D016477:Artifacts; D001718:Birefringence; D004867:Equipment Design; D006801:Humans; D008962:Models, Theoretical; D009412:Nerve Fibers; D009898:Optic Disk / Q000166:cytology*; D057109:Scanning Laser Polarimetry / Q000295:instrumentation / Q000379:methods*; D012590:Sclera / Q000166:cytology; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*