title: Grating interferometer with extremely high stability, suitable for measuring small refractive index changes.
abstract: We describe here a grating interferometer with extremely high stability and which can be used as a differential refractometer. The instrument uses heterodyne techniques to achieve high sensitivity. We present an analysis of the operation of the system and results which show that it has a long term stability of the order of 1/1500 wavelength over 2 h.
authors.forename: T H
authors.initials: TH
authors.lastname: Barnes
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: T
authors.initials: T
authors.lastname: Eiju
authors.forename: K
authors.initials: K
authors.lastname: Matsuda
authors.forename: N
authors.initials: N
authors.lastname: Ooyama