Common-path achromatic interferometer-coronagraph: images from a breadboard demonstrator.
A three-dimensional common-path interferometer is proposed, which can achromatically null out an on-axis source while maintaining the detectability of an off-axis source. A geometric phase in the three-dimensional interferometer introduces an achromatic pi-phase shift to the light from the on-axis source, such that destructive interference nulls out the axial light at one of the ports of the interferometer. Light from the off-axis source, which is exempt from destructive interference, comes out from both ports with equal intensity. The common-path scheme makes the system highly immune to environmental disturbances. In the described experiment, a 6x10(-6) peak-to-peak nulling contrast was obtained.
Tavrov
Alexander V
AV
National Astronomical Observatory of Japan, Tokyo, Japan. alxandtv@cc.nao.ac.jp
Nishikawa
Jun
J
Tamura
Motohide
M
Abe
Lyu
L
Yokochi
Kaito
K
Kurokawa
Takashi
T
Takeda
Mitsuo
M