Grating interferometer with extremely high stability, suitable for measuring small refractive index changes.
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.
Barnes
T H
TH
Matsumoto
K
K
Eiju
T
T
Matsuda
K
K
Ooyama
N
N