title: Multi-channel far-infrared HL-2A interferometer-polarimeter.
abstract: An HL-2A interferometer is upgraded to a multi-channel interferometer∕polarimeter, which includes four chords for the interferometer and four chords for the polarimeter. The far-infrared lasers (at λ = 432.5 μm and 30 mW power) are used to probe plasmas horizontally in the midplane of HL-2A. A conventional heterodyne technique is used for the interferometer. Two counter-rotating circularly polarized waves are used to measure the Faraday rotation effect. A fast-phase comparator with temporal resolution of 1 μs and phase resolution 0.1° is developed. Further, the distortion of the polarization caused by the beam-splitters and the other optical components is also investigated.
authors.affiliation: Southwestern Institute of Physics, Chengdu, Sichuan 610041, China. zhouy@swip.ac.cn
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.forename: Z C
authors.initials: ZC
authors.lastname: Deng
authors.forename: Y G
authors.initials: YG
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Yi