Two-color CO/sub 2/ interferometer with single Bragg cell and improved vibration compensation at 3. 39. mu. m

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1140148· OSTI ID:6906369

Innocente, P; Martini, S

A single-chord CO/sub 2/ (10.6-..mu..m) He--Ne (3.39-..mu..m) two-color laser interferometer which has been developed for the ETA-BETA II RFP machine is presented. Compared to the usual 0.633-..mu..m vibration compensation systems, the 3.39-..mu..m interferometer allows faster optical path-length variations to be measured without losing fringes, can stand larger angular deflections of the beams (e.g., due to vibrations of the optic mounts) without losing alignment, and uses the same acousto-optic modulator as the CO/sub 2/ system, thus minimizing the differences in the optical path of the two interferometers. The instrument has been extensively utilized on ETA-BETA II, where line density variations larger than 10/sup 20/ m/sup -2/ and occurring in less than 4 ..mu..s can be routinely measured and the residual error after vibration compensation is approx. =2 x 10/sup 18/ m/sup -2/. Some further developments of the diagnostic are presented, which are presently underway or planned.

• Research Organization: Istituto Gas Ionizzati, Associazione Euratom-ENEA-CNR, Via Gradenigo 6/A-35131 Padova, Italy
• OSTI ID: 6906369
• Journal Information: Rev. Sci. Instrum.; (United States), Vol. 59:8
• Country of Publication: United States
• Language: English

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