Design of a high-numerical-aperture miniature microscope objective for an endoscopic fiber confocal reflectance microscope

An endoscopic confocal microscope requires a high-performance, miniaturized microscope objective. We present the design of a miniature water-immersion microscope objective that is approximately 10 times smaller in length than a typical commercial objective. The miniature objective is 7 mm in outer diameter and 21 mm in length (from object to image). It is used in a fiber confocal reflectance microscope. The miniature microscope objective has a numerical aperture of 1.0, a field of view of 250 µm, and a working distance of 450 µm. It delivers diffraction-limited performance at λ = 1064 nm. Micro-meter-level resolution has been experimentally demonstrated.