Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-19T07:38:06.943Z Has data issue: false hasContentIssue false

THz Pulse Spectroscopy of Dynamic Plasmas: A New Diagnostic Tool

Published online by Cambridge University Press:  31 January 2011

Brian H. Kolner*
Affiliation:
[email protected], University of California, Davis, Applied Science, Davis, California, United States
Get access

Abstract

Rapidly evolving plasmas represent a challenging environment for both study and control. Density, collision frequency and temperature fluctuations can change over orders of magnitude on time scales of one ns with spatial features less than one cm and thus are not amenable to conventional continuous-wave diagnostic techniques such as microwave or mm-wave interferometry. We have developed a new technique for studying plasmas undergoing rapid nonequilibrium changes that uses THz time-domain spectroscopy (THz-TDS) in conjunction with optical fluorescence imaging. The advantages of using THz pulses lie in the fact that the broad bandwidth of a THz pulse contains frequency components both above and below the plasma frequency allowing a single ps-duration pulse to carry away information about the complex path-integrated susceptibility. Transverse fluorescence gives us a model of the longitudinal plasma distribution and using a novel rms error-minimization technique we can recover the real and imaginary parts of the susceptibility with <5 mm spatial and, potentially, ps time resolution (we are currently limited by S/N considerations to averaging over several THz pulses and thus obtain 40 ns resolution). From this we obtain the electron density and collision frequency, spatially and temporally resolved, with dynamic range >103. The principle of this new technique will be discussed along with results on a pulsed DC-discharge plasma. We will also present some new ideas such as concurrent molecular spectroscopy and computed tomography.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Koleczko, A. Ehrhardt, W. Kelzenberg, S. and Eisenreich, N. Propellants, Explosives, Pyrotechnics 26, 75 (2001).Google Scholar
[2] Pilla, G. Galley, D. Lacoste Françoise, D. A., Veynante, D. and Laux, C. O. IEEE Trans. Plasma Sci. 34, 2471 (2006).Google Scholar
[3] Starikovskaia, S. M. Kukaev, E. N. Kuksin, A. Yu. Nudnova, M. M. and Starikovskii, A. Yu. IEEE Trans. Plasma Sci. 36, 904 (2008).Google Scholar
[4] Krompholz, H. G. Hatfield, L. L., Neuber, A. A. Kohl, K. P. Chaparro, J. E. and Ryu, H.-Y. IEEE Trans. Plasma Sci. 34, 927 (2006).Google Scholar
[5] Felsenthal, P. and Proud, J. M. Phys. Rev. 139, A1796 (1965).Google Scholar
[6] Niayesh, K. Hashemi, E. Agheb, E. and Jadidian, J. IEEE Trans. Plasma Sci. 36, 930 (2008).Google Scholar
[7] Vasilyak, L. M. Kostyuchenko, S. V. Kudryavtsev, N. N. and Filyugin, I. V. Phys. Uspekhi 37, 247 (1994).Google Scholar
[8] Wagenaars, E. Bowden, M. D. and Kroesen, G. M. W. Phys. Rev. Lett. 98, 075002 (2007).Google Scholar
[9] Anikin, N. B. Zaviolava, N. A. Starikovskaia, S. M. and Starikovskii, A. Yu. IEEE Trans. Plasma Sci. 36, 902 (2008).Google Scholar
[10] Walton, S. G. Leonhardt, D. and Fernsler, R. F. IEEE Trans. Plasma Sci. 33, 838 (2005).Google Scholar
[11] Ekdahl, C. et al. , IEEE Trans. Plasma Sci. 33, 892 (2005).Google Scholar
[12] Lauer, E. J. Caporaso, G. J. Chambers, F. W. Chen, Y.-J. Falabella, S. Guethlein, G. McCarrick, J. Richardson, R. Sampayan, S. and Weir, J. in Beams 2002: 14th International Conference on High Power Particle Beams, eds. Melhorn, T. A. and Sweeney, M. A. (American Institute of Physics, 2002), pp. 248251.Google Scholar
[13] Huddletsone, R. H. and Leonard, S. L. eds., Plasma Diagnostic Techniques (Academic Press, 1965).Google Scholar
[14] Heald, M. A. and Wharton, C. B. Plasma Diagnostics with Microwaves (John Wiley and Sons, 1965).Google Scholar
[15] Luhmann, N. C. Jr. , in Infrared and Millimeter Waves, ed. Button, K. J. (Academic Press, 1979), Vol. 2, chap. 1, pp. 165.Google Scholar
[16] Verón, D., in Infrared and Millimeter Waves, ed. Button, K. J. (Academic Press, 1979), Vol. 2, chap. 2, pp. 67135.Google Scholar
[17] Benk, E. C. Golubiatnikov, G. Y. Fraser, G. T. Ji, B. Motika, S. A. and Karwacki, E. J. J. Vac. Sci. Technol. B 21, 2067 (2003).Google Scholar
[18] Exter, M. van, Fattinger, C. and Grischkowsky, D. Opt. Lett. 14, 1128 (1989).Google Scholar
[19] Cheville, R. A. and Grischkowsky, D. Opt. Lett. 20, 1646 (1995).Google Scholar
[20] Harde, H. Cheville, R. A. and Grischkowsky, D. J. Phys. Chem. A 101, 3646 (1997).Google Scholar
[21] Harde, H. Zhao, J. Wolff, M. Cheville, R. A. and Grischkowsky, D. J. Phys. Chem. A 105, 6038 (2001).Google Scholar
[22] Kolner, B. H. Buckles, R. A. Conklin, P. M. and Scott, R. P. IEEE J. Select. Topics Quantum Electron. 14, 505 (2008).Google Scholar
[23] Luque, J. Juchmann, W. Brinkman, E. A. and Jeffries, J. B. J. Vac. Sci. Technol. A 16, 397 (1998).Google Scholar
[24] Faris, G. W. Brinkman, E. A. and Jeffries, J. B. Opt. Exp. 7, 447 (2000).Google Scholar
[25] Chen, F. F. Introduction to Plasma Physics and Controlled Fusion (Plenum Press, 1984), 2nd edn.Google Scholar
[26] Kolner, B. H. Conklin, P. M. Buckles, R. A. Fontaine, N. K. and Scott, R. P. Appl. Phys. Lett. 87, 151501(1) (2005).Google Scholar
[27] Cormack, A. M. J. Appl. Phys. 34, 2722 (1963).Google Scholar
[28] Macovski, A. Medical Imaging Systems (Prentice-Hall, 1983).Google Scholar
[29] Bracewell, R. N. Aust. J. Phys. 9, 198 (1956).Google Scholar
[30] Bracewell, R. N. and Riddle, A. C. Astrophys. J. 150, 427 (1967).Google Scholar
[31] Deans, S. R. The Radon Transform and Some of Its Applications (John Wiley & Sons, 1983).Google Scholar
[32] Koslover, R. and McWilliams, R. Rev. Sci. Inst. 57, 2441 (1986).Google Scholar
[33] Stopper, U. Lindner, P. and Schumacher, U. Rev. Sci. Inst. 78, 043508 (2007).Google Scholar