title: High-sensitivity anastigmatic imaging needle for optical coherence tomography.
abstract: We present a high-optical-quality imaging needle for optical coherence tomography (OCT) that achieves sensitivity and resolution comparable to conventional free-space OCT sample arms. The side-viewing needle design utilizes total internal reflection from an angle-polished fiber tip, encased in a glass microcapillary. Fusion of the capillary to the fiber provides a robust, optical-quality output window. The needle's focusing optics are based on an astigmatism-free design, which exploits the "focal shift" phenomenon for focused Gaussian beams to achieve equal working distances (WDs) for both axes. We present a fabricated needle with a WD ratio of 0.98 for imaging in an aqueous environment. Our needle achieves the highest sensitivity of currently reported OCT imaging needles (112 dB), and we demonstrate its performance by superficial imaging of human skin and 3D volumetric imaging within a biological sample.
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Crawley, WA 6009, Australia. lscolaro@graduate.uwa.edu.au
authors.forename: Loretta
authors.initials: L
authors.lastname: Scolaro
authors.forename: Dirk
authors.initials: D
authors.lastname: Lorenser
authors.forename: Robert A
authors.initials: RA
authors.lastname: McLaughlin
authors.forename: Bryden C
authors.initials: BC
authors.lastname: Quirk
authors.forename: Rodney W
authors.initials: RW
authors.lastname: Kirk
authors.forename: David D
authors.initials: DD
authors.lastname: Sampson
mesh_terms: D016477:Artifacts; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007909:Lenses; D009339:Needles; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000295:instrumentation*