Endoscopic illuminating and imaging systems and methods

The present disclosure generally pertains to endoscopes configured to utilize a single optical channel for both image extraction and illumination. In certain embodiments, the disclosure contemplates an endoscope configured with a source of illumination outside of the visible spectrum, such as ultraviolet (UV) light, with the endoscope configured to down-convert such illumination into visible light at the distal end of the endoscope. This configuration not only avoids or reduces image flooding caused by the unwanted reflections on optical surfaces within the endoscope relays and objective, but also doubles the effective area of the lenses, thereby allowing higher quality imaging.