title: A scanning, all-fiber Sagnac interferometer for high resolution magneto-optic measurements at 820 nm.
abstract: The Sagnac Interferometer has historically been used for detecting non-reciprocal phenomena, such as rotation. We demonstrate an apparatus in which this technique is employed for high resolution measurements of the Magneto-Optical Polar Kerr effect-a direct indicator of magnetism. Previous designs have incorporated free-space components which are bulky and difficult to align. We improve upon this technique by using all fiber-optic coupled components and demonstrate operation at a new wavelength, 820 nm, with which we can achieve better than 1 μrad resolution. Mounting the system on a piezo-electric scanner allows us to acquire diffraction limited images with 1.5 μm spatial resolution. We also provide extensive discussion on the details and of the Sagnac Interferometer's construction.
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fried
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Fejer
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Aharon
authors.initials: A
authors.lastname: Kapitulnik