Kumar, Deepak and Bellan, Paul M. (2006) Heterodyne interferometer with unequal path lengths. Review of Scientific Instruments, 77 (8). Art. No. 083503. ISSN 0034-6748. doi:10.1063/1.2336769. https://resolver.caltech.edu/CaltechAUTHORS:KUMrsi06
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Abstract
Laser interferometry is an extensively used diagnostic for plasma experiments. Existing plasma interferometers are designed on the presumption that the scene and reference beam path lengths have to be equal, a requirement that is costly in both the number of optical components and the alignment complexity. It is shown here that having equal path lengths is not necessary, instead, what is required is that the path length difference be an even multiple of the laser cavity length. This assertion has been verified in a heterodyne laser interferometer that measures typical line-average densities of ~10^21/m^2 with an error of ~10^(19)/m^2.
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| Additional Information: | © 2006 American Institute of Physics. (Received 22 May 2006; accepted 24 July 2006; published online 24 August 2006) Helpful discussions with Professor William B. Bridges and Professor Kerry Vahala on laser phase autocorrelation are gratefully acknowledged. We would also like to thank Dr. Heun-Jin Lee for his technical help in setting up the Michelson interferometer in Fig. 2 and Gunsu Yun for spectroscopic measurements. In addition, we would like to recognize the helpful initial guidance from Dr. Raymond P. Golingo, University of Washington, Seattle, in designing the heterodyne interferometer. This work was supported by USDOE Grant No. DE-FG02–04ER54755. | |||||||||
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| Subject Keywords: | light interferometry; plasma diagnostics; plasma density; plasma toroidal confinement | |||||||||
| Issue or Number: | 8 | |||||||||
| DOI: | 10.1063/1.2336769 | |||||||||
| Record Number: | CaltechAUTHORS:KUMrsi06 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:KUMrsi06 | |||||||||
| Official Citation: | Heterodyne interferometer with unequal path lengths Deepak Kumar and Paul M. Bellan Rev. Sci. Instrum. 77, 083503 (2006); http://dx.doi.org/10.1063/1.2336769 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 3806 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Tony Diaz | |||||||||
| Deposited On: | 18 Sep 2006 | |||||||||
| Last Modified: | 08 Nov 2021 20:12 |
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