Abstract

Optical nonlinearities of black-tea extract dissolved in water are studied using the Z-scan and the four-wave mixing techniques with 7-ns, 532-nm pulses from a Q-switched Nd:YAG laser. The magnitude of the third-order nonlinear optical susceptibility of tea in water is comparable with that of carbon disulfide. The nonlinearity is identified to be of thermal origin.

© 1994 Optical Society of America

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References

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  1. D. S. Chemla and J. Zyss, eds., Nonlinear Optical Properties of Organic Molecules and Crystal (Academic, New York, 1987), Vols. 1 and 2.
  2. G. Carter and J. Zyss, eds., Feature on nonlinear organic materials, J. Opt. Soc. Am. B4, 942–1054 (1987).
  3. H.-J. Zhang, J.-H. Dai, P.-Y. Wang, and L.-A. Wu, “Self-focusing and self-trapping in new types of Kerr media with large nonlinearities,” Opt. Lett. 14, 695–696 (1989).
    [Crossref] [PubMed]
  4. H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
    [Crossref]
  5. M. Lai and J.-C. Diels, “Thermal nonlinear effects in exotic media: application to the study of nonlinear interfaces,” Appl. Opt. 29, 3882–3885 (1990).
    [Crossref] [PubMed]
  6. K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
    [Crossref]
  7. The “BRISK” Tea, Thomas J. Lipton, Inc., Englewood Cliffs, N.J. 07632.
  8. G. W. Sanderson, “The chemistry of tea and tea manufacturing,” in Structural and Functional Aspects of Phytochemistry, V. C. Runeckle and T. C. Tso, eds. (Academic, New York, 1978), pp. 247–316.
  9. E. A. H. Roberts and D. M. Williams, “The phenolic substances of manufactured tea. III. Ultra-violet and visible absorption spectra,” J. Sci. Food Agric. 9, 217–223 (1958).
    [Crossref]
  10. E. W. Chappelle, F. M. Wood, W. W. Newcomb, and J. E. McMurtey, “Laser-induced fluorescence of green plants. 3. LIF spectral signatures of five major plant types,” Appl. Opt. 24, 74–80 (1985).
    [Crossref] [PubMed]
  11. M. Sheik-Bahae, A. A. Said, and E. W. Van Stryland, “High-sensitivity, single-beam n2measurements,” Opt. Lett. 14, 955–957 (1989).
    [Crossref] [PubMed]
  12. M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
    [Crossref]
  13. P. N. Butcher and D. Cotter, The Elements of Nonlinear Optics (Cambridge U. Press, Cambridge, 1990), pp. 306–308.
    [Crossref]
  14. The numerical factor K used in Ref. 13 is absorbed in our definition of χ(3). In Ref. 13, P(n)= ∊0K(n)χ(n)|E|n.
  15. A. Yariv, Optical Electronics, 3rd ed. (Holt, Rinehart, and Winston, New York, 1985), p. 503.
  16. L. Yang, R. Dorsinville, Q. Z. Wang, P. X. Pe, R. R. Alfano, R. Zamboni, and C. Taliani, “Excited-state nonlinearity in polythiophene thin films investigated by the Z-scan technique,” Opt. Lett. 17, 323–325 (1992).
    [Crossref] [PubMed]
  17. A. C. Eckbreth, “BOXCARS: crossed-beam phase-matched CARS generation in gases,” Appl. Phys. Lett. 32, 421–423 (1978).
    [Crossref]
  18. A. R. Bogdan, Y. Prior, and N. Bloembergen, “Pressure-induced degenerate frequency resonance in four-wave light mixing,” Opt. Lett. 6, 82–83 (1981).
    [Crossref] [PubMed]
  19. G. M. Carter, “Excited-state dynamics and temporally resolved nonresonant nonlinear-optical processes in polydiacetylenes,” J. Opt. Soc. Am. B 4, 1018–1024 (1987).
    [Crossref]
  20. G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
    [Crossref]
  21. L. Yang, R. Dorsinville, Q. Z. Wang, W. K. Zou, P. P. Ho, N. L. Yang, R. R. Alfano, R. Zamboni, R. Danieli, G. Ruani, and C. Taliani, “Third-order optical nonlinearity in polycondensed thiophene-based polymers and polysilane polymers,” J. Opt. Soc. Am. B 6, 753–756 (1989).
    [Crossref]
  22. For a thin sample Lα= [1 − exp(−αL)]/α, the effective length of the sample. However, for a thick sample Lα has to be determined from a fit of the FWM signal to Eqs. (6) and (7) with the overlap of the pump and probe beams taken into consideration.
  23. D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
    [Crossref]
  24. H. J. Eichler, P. Günter, and D. W. Pohl, Laser-Induced Dynamic Gratings (Springer-Verlag, New York, 1986), pp. 127–140.
  25. The strong stray He–Ne light background in this experiment plays the role of a reference beam and leads to an effective heterodyne detection scheme as described on p. 30 of Ref. 24. Thus the time that it takes for the signal to decay to 1/e of its initial value is τ, not τ/2 as obtained for direct detection as discussed on p. 128 of Ref. 24 and in Ref. 27.
  26. R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
    [Crossref]
  27. H. J. Hoffman, “Thermally induced degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 552–562 (1986).
    [Crossref]
  28. H. J. Hoffman and P. E. Perkins, “Experimental investigations of thermally stimulated degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 563–568 (1986).
    [Crossref]

1992 (1)

1991 (1)

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

1990 (2)

M. Lai and J.-C. Diels, “Thermal nonlinear effects in exotic media: application to the study of nonlinear interfaces,” Appl. Opt. 29, 3882–3885 (1990).
[Crossref] [PubMed]

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

1989 (4)

1987 (1)

1986 (2)

H. J. Hoffman, “Thermally induced degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 552–562 (1986).
[Crossref]

H. J. Hoffman and P. E. Perkins, “Experimental investigations of thermally stimulated degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 563–568 (1986).
[Crossref]

1985 (2)

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

E. W. Chappelle, F. M. Wood, W. W. Newcomb, and J. E. McMurtey, “Laser-induced fluorescence of green plants. 3. LIF spectral signatures of five major plant types,” Appl. Opt. 24, 74–80 (1985).
[Crossref] [PubMed]

1983 (1)

R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
[Crossref]

1981 (1)

1978 (1)

A. C. Eckbreth, “BOXCARS: crossed-beam phase-matched CARS generation in gases,” Appl. Phys. Lett. 32, 421–423 (1978).
[Crossref]

1973 (1)

D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
[Crossref]

1958 (1)

E. A. H. Roberts and D. M. Williams, “The phenolic substances of manufactured tea. III. Ultra-violet and visible absorption spectra,” J. Sci. Food Agric. 9, 217–223 (1958).
[Crossref]

Abeleldayem, H.

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Alfano, R. R.

Anderson, D. R.

H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
[Crossref]

Barker, J. A.

R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
[Crossref]

Bloembergen, N.

Bogdan, A. R.

Butcher, P. N.

P. N. Butcher and D. Cotter, The Elements of Nonlinear Optics (Cambridge U. Press, Cambridge, 1990), pp. 306–308.
[Crossref]

Carter, G. M.

G. M. Carter, “Excited-state dynamics and temporally resolved nonresonant nonlinear-optical processes in polydiacetylenes,” J. Opt. Soc. Am. B 4, 1018–1024 (1987).
[Crossref]

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

Chandra Sekhar, P.

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Chappelle, E. W.

Chen, Y. J.

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

Cotter, D.

P. N. Butcher and D. Cotter, The Elements of Nonlinear Optics (Cambridge U. Press, Cambridge, 1990), pp. 306–308.
[Crossref]

Dai, J.-H.

Danieli, R.

Desai, R. C.

R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
[Crossref]

Diels, J.-C.

Dorsinville, R.

Eckbreth, A. C.

A. C. Eckbreth, “BOXCARS: crossed-beam phase-matched CARS generation in gases,” Appl. Phys. Lett. 32, 421–423 (1978).
[Crossref]

Eichler, H. J.

H. J. Eichler, P. Günter, and D. W. Pohl, Laser-Induced Dynamic Gratings (Springer-Verlag, New York, 1986), pp. 127–140.

George, M. C.

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Günter, P.

H. J. Eichler, P. Günter, and D. W. Pohl, Laser-Induced Dynamic Gratings (Springer-Verlag, New York, 1986), pp. 127–140.

Hagan, D. J.

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

He, K. X.

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Ho, P. P.

Hoffman, H. J.

H. J. Hoffman, “Thermally induced degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 552–562 (1986).
[Crossref]

H. J. Hoffman and P. E. Perkins, “Experimental investigations of thermally stimulated degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 563–568 (1986).
[Crossref]

Hryniewicz, J. V.

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

Irniger, V.

D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
[Crossref]

Korpel, A.

H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
[Crossref]

Lai, M.

Levenson, M. D.

R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
[Crossref]

Lin, H. H.

H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
[Crossref]

McMurtey, J. E.

Mehrl, D.

H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
[Crossref]

Newcomb, W. W.

Pe, P. X.

Perkins, P. E.

H. J. Hoffman and P. E. Perkins, “Experimental investigations of thermally stimulated degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 563–568 (1986).
[Crossref]

Pohl, D. W.

D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
[Crossref]

H. J. Eichler, P. Günter, and D. W. Pohl, Laser-Induced Dynamic Gratings (Springer-Verlag, New York, 1986), pp. 127–140.

Prior, Y.

Roberts, E. A. H.

E. A. H. Roberts and D. M. Williams, “The phenolic substances of manufactured tea. III. Ultra-violet and visible absorption spectra,” J. Sci. Food Agric. 9, 217–223 (1958).
[Crossref]

Ruani, G.

Said, A. A.

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

M. Sheik-Bahae, A. A. Said, and E. W. Van Stryland, “High-sensitivity, single-beam n2measurements,” Opt. Lett. 14, 955–957 (1989).
[Crossref] [PubMed]

Sanderson, G. W.

G. W. Sanderson, “The chemistry of tea and tea manufacturing,” in Structural and Functional Aspects of Phytochemistry, V. C. Runeckle and T. C. Tso, eds. (Academic, New York, 1978), pp. 247–316.

Schwarz, S. E.

D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
[Crossref]

Sheik-Bahae, M.

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

M. Sheik-Bahae, A. A. Said, and E. W. Van Stryland, “High-sensitivity, single-beam n2measurements,” Opt. Lett. 14, 955–957 (1989).
[Crossref] [PubMed]

Taliani, C.

Thakur, M. K.

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

Van Stryland, E. W.

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

M. Sheik-Bahae, A. A. Said, and E. W. Van Stryland, “High-sensitivity, single-beam n2measurements,” Opt. Lett. 14, 955–957 (1989).
[Crossref] [PubMed]

Venkateswarlu, P.

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Wang, P.-Y.

Wang, Q. Z.

Wei, T.-H.

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

Williams, D. M.

E. A. H. Roberts and D. M. Williams, “The phenolic substances of manufactured tea. III. Ultra-violet and visible absorption spectra,” J. Sci. Food Agric. 9, 217–223 (1958).
[Crossref]

Wood, F. M.

Wu, L.-A.

Yang, L.

Yang, N. L.

Yariv, A.

A. Yariv, Optical Electronics, 3rd ed. (Holt, Rinehart, and Winston, New York, 1985), p. 503.

Zamboni, R.

Zhang, H.-J.

Zou, W. K.

Appl. Opt. (2)

Appl. Phys. Lett. (2)

A. C. Eckbreth, “BOXCARS: crossed-beam phase-matched CARS generation in gases,” Appl. Phys. Lett. 32, 421–423 (1978).
[Crossref]

G. M. Carter, M. K. Thakur, Y. J. Chen, and J. V. Hryniewicz, “Time and wavelength resolved nonlinear optical spectroscopy of a polydiacetylene in the solid state using picosecond dye laser pulses,” Appl. Phys. Lett. 47, 457–459 (1985).
[Crossref]

IEEE J. Quantum Electron. (3)

H. J. Hoffman, “Thermally induced degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 552–562 (1986).
[Crossref]

H. J. Hoffman and P. E. Perkins, “Experimental investigations of thermally stimulated degenerate four-wave mixing,” IEEE J. Quantum Electron. QE-22, 563–568 (1986).
[Crossref]

M. Sheik-Bahae, A. A. Said, T.-H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[Crossref]

J. Opt. Soc. Am. B (2)

J. Sci. Food Agric. (1)

E. A. H. Roberts and D. M. Williams, “The phenolic substances of manufactured tea. III. Ultra-violet and visible absorption spectra,” J. Sci. Food Agric. 9, 217–223 (1958).
[Crossref]

Opt. Commun. (1)

K. X. He, H. Abeleldayem, P. Chandra Sekhar, P. Venkateswarlu, and M. C. George, “Transient multiple diffraction rings induced by ultrafast laser from Chinese tea,” Opt. Commun. 81, 101–105 (1991).
[Crossref]

Opt. Lett. (4)

Opt. News (1)

H. H. Lin, A. Korpel, D. Mehrl, and D. R. Anderson, “Nonlinear Chinese tea,” Opt. News 15(12), 55 (1989).
[Crossref]

Phys. Rev. A (1)

R. C. Desai, M. D. Levenson, and J. A. Barker, “Forced Rayleigh scattering: thermal and acoustic effects in phase-conjugate wave-front generation,” Phys. Rev. A 27, 1968–1976 (1983).
[Crossref]

Phys. Rev. Lett. (1)

D. W. Pohl, S. E. Schwarz, and V. Irniger, “Forced Rayleigh scattering,” Phys. Rev. Lett. 31, 32–35 (1973).
[Crossref]

Other (10)

H. J. Eichler, P. Günter, and D. W. Pohl, Laser-Induced Dynamic Gratings (Springer-Verlag, New York, 1986), pp. 127–140.

The strong stray He–Ne light background in this experiment plays the role of a reference beam and leads to an effective heterodyne detection scheme as described on p. 30 of Ref. 24. Thus the time that it takes for the signal to decay to 1/e of its initial value is τ, not τ/2 as obtained for direct detection as discussed on p. 128 of Ref. 24 and in Ref. 27.

For a thin sample Lα= [1 − exp(−αL)]/α, the effective length of the sample. However, for a thick sample Lα has to be determined from a fit of the FWM signal to Eqs. (6) and (7) with the overlap of the pump and probe beams taken into consideration.

D. S. Chemla and J. Zyss, eds., Nonlinear Optical Properties of Organic Molecules and Crystal (Academic, New York, 1987), Vols. 1 and 2.

G. Carter and J. Zyss, eds., Feature on nonlinear organic materials, J. Opt. Soc. Am. B4, 942–1054 (1987).

The “BRISK” Tea, Thomas J. Lipton, Inc., Englewood Cliffs, N.J. 07632.

G. W. Sanderson, “The chemistry of tea and tea manufacturing,” in Structural and Functional Aspects of Phytochemistry, V. C. Runeckle and T. C. Tso, eds. (Academic, New York, 1978), pp. 247–316.

P. N. Butcher and D. Cotter, The Elements of Nonlinear Optics (Cambridge U. Press, Cambridge, 1990), pp. 306–308.
[Crossref]

The numerical factor K used in Ref. 13 is absorbed in our definition of χ(3). In Ref. 13, P(n)= ∊0K(n)χ(n)|E|n.

A. Yariv, Optical Electronics, 3rd ed. (Holt, Rinehart, and Winston, New York, 1985), p. 503.

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Figures (10)

Fig. 1
Fig. 1

Absorption spectrum of a dilute tea solution in water at room temperature. The solution was contained in a glass optical cell of path length 1 cm.

Fig. 2
Fig. 2

Fluorescence spectrum of a black tea solution in water at room temperature for excitation at 514.5 nm. The vertical arrow represents the peak position for chlorophyll fluorescence, which is much weaker for solution in water than in alcohol.

Fig. 3
Fig. 3

Schematic diagram of the experimental arrangement for the Z-scan measurements, showing both closed-aperture (S < 1) and open-aperture (S = 1) configurations.

Fig. 4
Fig. 4

Typical (a) closed-aperture (S = 0.23) and (b) open-aperture (S = 1) Z-scan data for a tea solution in water. The solid curve in (b) is a theoretical fit of the experimental data, represented by squares, to Eq. (4).

Fig. 5
Fig. 5

Folded BOXCARS beam geometry of the forward DFWM experiment.

Fig. 6
Fig. 6

Schematic diagram of the experimental arrangement for the forward-folded BOXCARS DFWM measurements. The probe-beam intensity is attenuated by a neutral-density filter (not shown) in its path. SHG, second-harmonic generator; A/D, analog-to-digital converter.

Fig. 7
Fig. 7

Intensity dependence of the DFWM signal (filled circles) and the diffraction efficiency (open squares). The solid line is a theoretical fit to the DFWM signal. A slope of 3 exhibits the expected cubic intensity dependence. The dashed line is a theoretical fit to the diffraction efficiency data. A slope of 2 verifies the quadratic dependence on intensity. Deviation from the straight lines at higher intensities is indicative of the onset of saturation effects.

Fig. 8
Fig. 8

Plot of the concentration dependence of the thermally induced nonlinear-optical susceptibility of the tea solution in water. The concentration is represented in terms of the linear absorption coefficient α of the solution at 532 nm.

Fig. 9
Fig. 9

Time evolution of the diffracted probe-beam intensity at two different crossing angles of the pump beams. The 7-ns, 532-nm pump pulses have a repetition rate of 10 Hz. The probe is the output of a cw He–Ne laser operating at 632.8 nm. Squares represent the data taken at the crossing angle θ = 67°, and circles represent the data taken at the crossing angle θ = 1°. The solid curves represent a single-exponential fit to the decaying part of the signal.

Fig. 10
Fig. 10

Inverse of the grating decay time 1/τ at various q2. The slope of the plot is the thermal diffusion coefficient D, and it is equal to 1.4 ± 0.1 × 10−3 cm2/s.

Tables (2)

Tables Icon

Table 1 Approximate General Analysis (%) of Black Teaa

Tables Icon

Table 2 Summary of the Results of Z-Scan Measurement for the Tea Solution in Water Characterized by 532-nm Linear Absorption Coefficient α = 1.4 cm−1

Equations (10)

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

χ R ( 3 ) = c n 0 2 160 π 2 γ ,
Δ n = n - n 0 = 2 λ 2 π L α Δ T p - v 0.406 ( 1 - S ) 0.25 ,
χ R ( 3 ) = ( n 0 n 0 r ) 2 L α r L α Δ T p - v Δ T p - v r I r I χ R r ( 3 ) ,
T ( z , S = 1 ) = m = 0 [ - q 0 ( z ) ] m ( m + 1 ) 3 / 2 ,
χ I ( 3 ) = λ c n 0 2 640 π 3 β ,
η d = I s / I p ,
χ ( 3 ) = 0 λ c n 0 2 2 π η d 1 / 2 L α I 1 I 2 ,
χ ( 3 ) χ r ( 3 ) = ( η d η d r ) 1 / 2 ( n 0 n 0 r ) 2 L α r L α ( I 1 r I 2 r I 1 I 2 ) 1 / 2 ,
τ = ρ C p κ q 2 ,
γ th = ξ α ρ C v d n d T τ p ,

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