A probe for an optical coherence tomography system according to an embodiment of the current invention includes a sheath having a proximal end and a distal end and defining a lumen therein, an optical fiber disposed at least partially within the lumen of said sheath, and a sapphire lens attached to the distal end of the sheath to form a fluid-tight seal to prevent fluid from entering the lumen of said sheath. The optical fiber has an end arranged in an optical path with the sapphire lens to provide optical coupling between the sapphire lens and the optical fiber.