Endoscopic micro-optical coherence tomography with extended depth of focus using a binary phase spatial filter

Micro-optical coherence tomography (mu OCT) is an advanced imaging technique that acquires a three-dimensional microstructure of biological samples with a high spatial resolution, up to 1 mu m, by using a broadband light source and a high numerical aperture (NA) lens. As high NA produces a short depth of focus (DOF), extending the DOF is necessary to obtain a reasonable imaging depth. However, due to the complexity of optics and the limited space, it has been challenging to fabricate endoscopic mu OCT, which is essential for clinical translation. Here, we report an endoscopic mu OCT probe with an extended DOF by using a binary phase spatial filter. The imaging results from latex beads demonstrated that the mu OCT probe achieved an axial resolution of 2.49 mu m and a lateral resolution of 2.59 mu m with a DOF extended by a factor of 2. The feasibility of clinical use was demonstrated by ex vivo imaging of the rabbit iliac artery. (C) 2017 Optical Society of America.National Research Foundation of Korea (NRF) (2015R1A1A1A05027209)

Multipoint scanning dual-detection confocal microscopy for fast 3D volumetric measurement

We propose a multipoint scanning dual-detection confocal microscopy (MS-DDCM) system for fast 3D volumetric measurements. Unlike conventional confocal microscopy, MS-DDCM can accomplish surface profiling without axial scanning. Also, to rapidly obtain 2D images, the MS-DDCM employs a multipoint scanning technique, with a digital micromirror device used to produce arrays of effective pinholes, which are then scanned. The MS-DDCM is composed of two CCDs: one collects the conjugate images and the other collects nonconjugate images. The ratio of the axial response curves, measured by the two detectors, provides a linear relationship between the height of the sample surface and the ratio of the intensity signals. Furthermore, the difference between the two images results in enhanced contrast. The normalising effect of the MS-DDCM provides accurate sample heights, even when the reflectance distribution of the surface varies. Experimental results confirmed that the MS-DDCM achieved high-speed surface profiling with improved image contrast capability.This work was supported in part by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (NRF-2014H1A2A1021417 and NRF-2014R1A2A1A10050330)