title: Note: Optical fiber milled by focused ion beam and its application for Fabry-Pérot refractive index sensor.
abstract: We introduce a highly compact fiber-optic Fabry-Pérot refractive index sensor integrated with a fluid channel that is fabricated directly near the tip of a 32 μm in diameter single-mode fiber taper. The focused ion beam technique is used to efficiently mill the microcavity from the fiber side and finely polish the end facets of the cavity with a high spatial resolution. It is found that a fringe visibility of over 15 dB can be achieved and that the sensor has a sensitivity of ~1731 nm/RIU (refractive index units) and a detection limit of ~5.78 × 10(-6) RIU. This miniature integrated all-in-fiber optofludic sensor may find use in minimal-invasive biomedical applications.
authors.affiliation: Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Wu
authors.initials: W
authors.lastname: Yuan
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Alexey
authors.initials: A
authors.lastname: Savenko
authors.forename: Dirch Hjorth
authors.initials: DH
authors.lastname: Petersen
authors.forename: Ole
authors.initials: O
authors.lastname: Bang