Abstract

A new method for noncontact, high-resolution measurement of gas density is described. The method uses a two-frequency Zeeman-split He–Ne laser and cumulative phase-measuring electronics. The measurement is resolved in two dimensions and provides density that is averaged only along the length of the laser beam that passes through the test section. The technique is based on highly accurate measurement of the optical path-length change of the laser beam as it passes through a test cell (in principle, to within 0.001λ, where λ is the wavelength of the laser). The technique also provides a very large dynamic range (again, in principle, up to 1010), which makes the method additionally attractive. Although the optical path length through the test section is directly related to the index of refraction, and hence to the density of the gas, the method can also be used to measure temperature (if the gas pressure is known) or pressure (if the temperature is known).

© 2001 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]

1994

1993

M. V. Ötügen, K. D. Annen, R. G. Seasholtz, “Gas temperature measurements using a dual-line detection Rayleigh scattering technique,” AIAA J. 31, 2098–2104 (1993).
[CrossRef]

1990

1989

1980

Annen, K. D.

M. V. Ötügen, K. D. Annen, R. G. Seasholtz, “Gas temperature measurements using a dual-line detection Rayleigh scattering technique,” AIAA J. 31, 2098–2104 (1993).
[CrossRef]

Baer, T.

Brown, T. M.

DeBarber, P. A.

DeWeerd, H.

M. Hercher, G. Wyntjes, H. DeWeerd, “Noncontact extensometer,” in Industrial Laser Interferometry, R. J. Pryputniewicz, ed., Proc. SPIE746, 185–191 (1987).
[CrossRef]

Fletcher, D. G.

Hall, J. L.

Hercher, M.

M. Hercher, G. Wyntjes, H. DeWeerd, “Noncontact extensometer,” in Industrial Laser Interferometry, R. J. Pryputniewicz, ed., Proc. SPIE746, 185–191 (1987).
[CrossRef]

Kowalski, F. V.

Laufer, G.

McKenzie, R. L.

Miles, R. B.

Nandula, S. P.

Ötügen, M. V.

M. V. Ötügen, K. D. Annen, R. G. Seasholtz, “Gas temperature measurements using a dual-line detection Rayleigh scattering technique,” AIAA J. 31, 2098–2104 (1993).
[CrossRef]

Pitz, R. W.

Seasholtz, R. G.

M. V. Ötügen, K. D. Annen, R. G. Seasholtz, “Gas temperature measurements using a dual-line detection Rayleigh scattering technique,” AIAA J. 31, 2098–2104 (1993).
[CrossRef]

Smith, M.

Smits, A.

Wyntjes, G.

M. Hercher, G. Wyntjes, H. DeWeerd, “Noncontact extensometer,” in Industrial Laser Interferometry, R. J. Pryputniewicz, ed., Proc. SPIE746, 185–191 (1987).
[CrossRef]

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Figures (4)

Fig. 1
Fig. 1

Experimental setup.

Fig. 2
Fig. 2

Results of pressure measurement (log scale).

Fig. 3
Fig. 3

Results of pressure measurement (linear scale).

Fig. 4
Fig. 4

Measurements in the low-pressure range.

Equations (8)

Equations on this page are rendered with MathJax. Learn more.

A=AR sin2πνt+AT sin2πν+Δνt+Θ.
A2=AR2sin22πνt+AT2sin22πν+Δνt+Θ-ARATcos2π2ν+Δνt+Θ+ARATcos2πΔνt+Θ,
S=CAR2+AT2/2+ARAT cos2πΔνt+Θ,
Δ=Ln0-n.
ρ=cn-1,
ρ=1-ΔLn0-1ρ0,
dρ=ρ0Ln0-1 dΔ,
dρ=4428L dΔ.

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