Heterodyne interferometer of coaxial CO2 and He-Ne lasers for plasma density measurements

Hidemi Takahashi, Minoru Kimura, Reiji Sano, Yoshio Nagayama, Kenro Miyamoto

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


An interferometer using coaxial CO2 and He-Ne lasers has been developed for electron density measurements in the reversed field pinch plasma. The interferometer uses the phase modulating heterodyne detection of 60 MHz. The CO2 laser interferometer is free from the mechanical vibrations due to the reduction of the vibrations by the air springs and the compensation of the vibrations by the He-Ne laser interferometer. The electron density measurement during a long-time discharge of 50 ms without the disturbance by the vibrations is achievable. The resolution is less than 1/100 fringe of the CO2 laser interferometer, therefore the electron line density as small as 1.1×1014 electrons/cm2 is detectable.

Original languageEnglish
Pages (from-to)1286-1289
Number of pages4
JournalReview of Scientific Instruments
Issue number7
Publication statusPublished - 1986
Externally publishedYes

ASJC Scopus subject areas

  • Instrumentation


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