The design of a second harmonic tangential array interferometer for C-Mod
| Autor: | J. Irby, N. Bretz, F. Jobes |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Review of Scientific Instruments. 68:713-716 |
| ISSN: | 1089-7623 0034-6748 |
| DOI: | 10.1063/1.1147683 |
| Popis: | A design for a tangential array interferometer for C-Mod operating at 1.06 and 0.53 μm is presented. This is a special type of two color interferometer in which a Nd:YAG laser is frequency doubled in a nonlinear crystal. Because the doubling efficiency is imperfect, two frequencies propagate collinearly through the plasma after which the 1.06 μm ray is doubled again mixing in the optical domain with the undoubled ray. The resulting interference is insensitive to path length but is affected by plasma dispersion in the usual way. A typical central fringe shift in C-Mod is expected to be 0.1–1.0, but the absolute and relative accuracy in nel measurements can be as high as in a conventional interferometer. This design uses a repetitively pulsed laser which is converted to a fan beam crossing the horizontal midplane. The chordal array is defined by internal retroreflectors on the C-Mod midplane which return the beam to the second doubler and a detector array. This interferometer design has beam diameters of a ... |
| Databáze: | OpenAIRE |
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