Fig. 1. Application diagram of multi-functional OCT combined with D-FFOCT diagnosis and treatment system

Fig. 2. Traditional and smart scanning protocols to obtain time intervals^［13］. (a) Traditional scanning protocol to obtain three-time intervals; (b) smart scanning protocol to obtain three-time intervals; (c) smart scanning protocol to obtain seven-time intervals

Fig. 3. Comparison of the en-face OCTA images reconstructed by averaging (a) and adaptive (b) multi-time interval algorithms with boxes which indicate ROI, these zooming areas are shown in (c) and (d). The corresponding 300th B-scan OCTA images are shown in (e) to (g), and the arrows indicate some significant signal-to-noise ratio and detail improvements^［13］

Fig. 4. Robot-assisted optical coherence tomography^［15］. (a) Schematic of the system setup with system components including SLD (super luminescent diode), circulator, fiber coupler (FC), parabolic collimator (C1, C2, and C3), mirror, polarization controller (PC1 and PC2), optical grating (G), prism (P), galvanometer scanner, CMOS and 6-axis robotic arm; (b) optical diagram of telecentric sample arm; (c) point spread function of the system; (d) USAF 1951 resolution card image for reading the lateral resolution, element 2 in group 7 can be seen

Fig. 5. High resolution vascular image of whole mouse brain^［15］. (a) Wide-field high resolution whole brain vascular image (size of 10 mm×8.1 mm with lateral resolution of 6 µm); (b) low resolution whole brain vascular image (size of 8.8 mm×8.8 mm with lateral resolution of 24 µm); (c)(e) zooming areas in red box of the high-resolution image, the image on the left of figure (e) is the profile of a single micro vessel which is used to demonstrate the lateral resolution; (d)(f) zooming areas in red box of the low-resolution image

Fig. 6. MIOCT scanner coupled onto the camera port of a commercial microscope^［20］ (the OCT beam traverses through the microscope optical zoom module and the OCT lateral resolution and field of view (FOV) are coupled to the microscope zoom level)

Fig. 7. MIOCT scanner integrates directly prior to the microscope objective (this design requires a telescope to magnify the OCT beam prior to the objective, but the OCT resolution and lateral FOV are independent of the microscope zoom level)^［21］

Fig. 8. Schematic of polarization isolation of CFBG-based SPML laser^［25］ (PBC/S: fiber polarization beam combiner/splitter; ILP: fiber optic in-line polarizer; IM: Mach-Zehnder intensity modulator; RF Amp: radio frequency amplifier; CFBG: chirped fiber Bragg grating; SOA: semiconductor optical amplifier; CIR: fiber optic circulator; PMF: polarization-maintaining fiber; solid blue two-way arrows indicate the axis of polarization of light in the PMF,and dashed blue arrows indicate the direction of light propagation)

Fig. 9. Characterization of ultra-high speed sweep-frequency OCT systems^［25］. (a) Time trace of swept laser output; (b) time trace of interferometric signal; (c) spectrum of swept laser; (d) unwrapped fringe phase (red line) of the corresponding interferometric signal (gray line); (e) axial resolution measured to be 9.5 µm in air from the point spread function; (f) relative group delay over a single cavity round trip

Fig. 10. Three distinct resolution modes^［36］. (a)‒(b) Live 4D-OCT using high-resolution mode with 120 nm bandwidth; (c)‒(f) intermediate mode with 17 nm bandwidth; (g)‒(k) long-range mode with 4 nm bandwidth; (a)(c) 3D views of a fingertip and a cannula; (b)(d) 3D views of a fingernail; (e)‒(f) 3D views of a caterpillar and a snail on a leaf; (g) 3D view of a researcher wearing laser protection glasses; (h)‒(i) 3D views of shaking hands and holding a cup; (j)‒(k) the corresponding 2D view and front view of the cup scene; the displayed images are taken from screen recordings of the live 4D-OCT software

Fig. 11. Schematic of D-FFOCT system (BS: beam splitter; OB: objectives; PZT: piezoelectric translation; TS: translation stage; YAG: yttrium aluminum garnet)

Fig. 12. Boundary between glioma and normal brain tissue of a mouse (from left to right, HE staining image, microscopy image, and D-FFOCT image are shown in turn)