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High Sensitivity Measurement of Flame Radicals by Frequency Modulation Spectroscopy

Published online by Cambridge University Press:  22 February 2011

Bernard A. Woody
Bernard A. Woody*
Affiliation:
United Technologies Research Center, Silver Lane, East Hartford, CT 06108
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Abstract

Frequency modulation spectroscopy (FMS) is a new combination of optical absorption spectroscopy and radio technology which increases absorption sensitivity by orders of magnitude. Extremely weak atomic and molecular lines and stronger absorbers at low number densities, previously accessible only to fluorescence techniques, are readily detected.

Information obtainable through FMS include species number density, lineshape and temperature. Data interpretation is straightforward without regard to such problems as quenching, alternate excited state reaction channel loss and source/absorber solid angle and spectral response calibration, since the technique probes the lower state population via line of sight, volume integration. Application of the technique to the study of radical species such as CH, CN, and NO2 produced in flames and low pressure reactor vessels has made absorption studies of these systems feasible for the first time. The technique has also been used to study such diverse problems as the effect of fuel additives on the production of soot, and the concentration and distribution of the chemical intermediates, BH, BO, and BO2, in microwave driven reactive flows. Feasibility studies to determine if FMS can assist in the diagnostic and control problems of chemical vapor deposition in the semiconductor industry have recently been initiated.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 117: Symposium C – Process Diagnostics: Materials, Combustion, Fusion , 1988 , 165
Copyright
Copyright © Materials Research Society 1988

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References

1. Harris, S.E., Oshman, M.K., McMurty, B.J., and Ammann, E.O., Appl. Phys. Lett. 7,185 (1965).CrossRefGoogle Scholar
2. Bjorklund, G.C., Opt. Lett. 5, 15 (1980).CrossRefGoogle Scholar
3. Bjorklund, G.C., Levenson, M.P., Lenth, W., and Ortiz, C., Appl. Phys. B, 32, 145 (1983).CrossRefGoogle Scholar
4. Woody, B.A. and Lynds, L., Appl. Opt. 25, (13), 2148 (1986).CrossRefGoogle Scholar
5. Hall, J.L., Hollberg, L., Baer, T., and Robinson, H.G., Appl. Phys. Lett. 39 (9), 680 (1981).CrossRefGoogle Scholar
6. Whittaker, E.A., Pokrowsky, P., Zapka, W., Roche, K., and Bjorklund, G.C., JQSRT, 30, (4), 289 (1983).CrossRefGoogle Scholar
7. Lynds, L. and Woody, B.A., Appl. Opt (accepted for publication).Google Scholar
8. Yariv, A., Introduction to Optical Electronics, (Holt, Rinehart and Winston, 1971).Google Scholar
9. Fishburne, E.S. and Rao, K.N., J.Mol. Spectrosc. 19, 290 (1966).CrossRefGoogle Scholar
10. Meredith, R.E. and Smith, F.G., Vol. 2, contract DAHC-15-67-C-0062 (Nov. 1971).Google Scholar
11. Bonczyk, P.A., (accepted for publication in Comb. Sci. and Technol.)Google Scholar
12. Gaydon, A. G. and Wolfhard, H.G., Flames: Their Structure, Radiation and Temperature, 4th Ed., (Halsted Press, 1979).Google Scholar
13. Hsu, D., Monts, K. and Zare, R.N., Spectral Atlas of Nitrogen Dioxide, (Academic Press, 1978).Google Scholar
14. Bonczyk, P.A. and Shirley, J.A., Comb. and Flame, 35, 253 (1979).CrossRefGoogle Scholar
15. Bulewicz, E.M., Padley, P.J., and Smith, R.E., Proc. Roy. Sci. A., 315, 129, (1970).Google Scholar
16. Whittaker, E.A., Wendt, H.R., Hunziker, H.E. and Bjorklund, G.C., Appl. Phys. B, 35, 105 (1984).CrossRefGoogle Scholar
17. Lenth, W. and Gehrtz, M., Appl. Phys. Lett, 47, 1263 (1985).CrossRefGoogle Scholar
18. Cooper, D.E. and Gallagher, T.F., Appl. Opt., 24 (5), 710 (1985).CrossRefGoogle Scholar
19. Lenth, W., Ortiz, C. and Bjorklund, G.C., Opt. Lett., 6 (7), 351 (1981).CrossRefGoogle Scholar
20. Tran, N.H., Kachru, R., Pillet, P., van Linden van den Heuvel, H.B., Gallagher, T.F. and Watjen, J.P., Appl. Opt., 23 (9), 1353 (1984).CrossRefGoogle Scholar