title: Multidimensional subwavelength position sensing using a semiconductor laser with optical feedback.
abstract: We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength λ≈1550 nm, we achieve an average nanoscale resolution of approximately 9.8 nm (~λ/160).
authors.forename: Seth D
authors.initials: SD
authors.lastname: Cohen
authors.forename: Andrés
authors.initials: A
authors.lastname: Aragoneses
authors.forename: Damien
authors.initials: D
authors.lastname: Rontani
authors.forename: M C
authors.initials: MC
authors.lastname: Torrent
authors.forename: Cristina
authors.initials: C
authors.lastname: Masoller
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gauthier