Confocal imaging through an endoscopic rod

Endoscopic rods (such as the Hopkins variety) are based on a tubular design containing a sequence of refractive optical structures1. They are intended to offer a wide angle of view but often at the expense of performance in terms of field curvature. They are used in areas of biomedicine that require visualisation of live tissue at the distal end, enabling clinicians to perform a variety of endoscopy procedures including biopsy.

Here we demonstrate a scanning confocal arrangement with the endoscopic rod used as an optical conduit, guiding the investigation beam to a resolution target placed at the distal end and guiding the backscattered light back to the detector.

The data presented in this study highlights the possible new contributions of this method to aid Optical Coherence Tomography (OCT) measurements in vivo and what could be expected of its application in terms of scanangle (field of view) and transmission performance