Hostname: page-component-745bb68f8f-s22k5 Total loading time: 0 Render date: 2025-02-10T12:17:30.472Z Has data issue: false hasContentIssue false
  • English
  • Français

Contributions of Low-Lying Excited States to Optical Nonlinearities in Squaraines

Published online by Cambridge University Press:  10 February 2011

K. D. Singer ,
J. H. Andrews ,
J. D. V. Khaydarov ,
D. L. Hull  and
K. C. Chuang
K. D. Singer
Affiliation:
Case Western Reserve University, Department of Physics, Cleveland, OH 44106-7079
J. H. Andrews
Affiliation:
Case Western Reserve University, Department of Physics, Cleveland, OH 44106-7079
J. D. V. Khaydarov
Affiliation:
Case Western Reserve University, Department of Physics, Cleveland, OH 44106-7079
D. L. Hull
Affiliation:
NASA Lewis Research Center, Cleveland, OH 44135-3191
K. C. Chuang
Affiliation:
NASA Lewis Research Center, Cleveland, OH 44135-3191
Get access

Abstract

We measured the third-harmonic spectrum for a series of both centrosymmetric and noncentrosymmetric squaraine dyes in chloroform. By fitting the experimental dispersion of the third order susceptibility, γ, to a four-level sum-over-states model, we determined the strength and location of the lowest lying two-photon-like transition. In each case, we find that the lowest two-photon-like state appears just above the dominant linear absorption peak in energy and that the transition moment to that state makes a significant contribution to the nonlinearity, as do transition moments to one or more higher-lying two-photon-like states in the ultraviolet. The spectra of one centrosymmetric dye contains an additional feature evidencing a nonzero dipole moment difference between the ground and first excited state dipole moments (δμ) that we attribute to a conformational asymmetry. A noncentrosymmetric squaraine dye shows a similar feature, which, as expected, arises from its δμ. Effects of symmetry breaking are described.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 413: Symposium W – Electrical, Optical, and Magnetic Properties of Organic Solid State Materials III , 1995 , 215
Copyright
Copyright © Materials Research Society 1996

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

REFERENCES

[1] Dirk, C. W. and Kuzyk, M. G., “Squarilium dye-doped polymer systems as quadratic electrooptic materials,” Chem. Mat. 2, 4–6 (1990).Google Scholar
[2] Andrews, J.H., Khaydarov, J.D.V., and Singer, K.D., “Contribution of the 2Ag State to the Third Order Optical Nonlinearity in a Squaraine Dye,” Opt. Lett. 19, 984–986, errata 19, 1909, (1994).Google Scholar
[3] Yu, Y. Z., Shi, R. F., Carito, A. F., and rossman, C. H.,”Origin of negative χ(3) in squaraines: experimental observation of two-photon state,” Opt. Lett. 19, 786–788 (1994).Google Scholar
[4] Zhou, Q. L., Shi, R. F., Zamani-Khamari, O., and Garito, A. F., “Negative third-order optical responses in squaraines,” Nonlinear Optics 6, 145–154 (1993).Google Scholar
[5] Andrews, J.H., Khaydarov, J.D.V., Singer, K.D., Hull, D.L., and Chuang, K.C., “Spectral Dispersion of Third Harmonic Generation in Squaraines”, Nonlinear Optics 10, 227 (1995).Google Scholar
[6] Dirk, C.W., Herndon, W.C., Cervantes-Lee, F., Selnau, H., Martinez, S., Kalamegham, P., Tan, A., Campos, G., Velez, M., Zyss, J., Ledoux, I., and Cheng, L.-T., “Squarilium Dyes: Structural Factors Pertaining to the Negative Third-Order Nonlinear Optical Response,”, it J. Am. Chem. Soc. 117, 2214 (1995).Google Scholar
[7] Kuzyk, M. G. and Dirk, C. W., “Effects of centrosymmetry on the nonresonant electronic third-order nonlinear optical susceptibility,” Phys. Rev. A 41, 5098–5109 (1990).Google Scholar
[8] Dirk, C. W., Cheng, L. -T., and Kuzyk, M. G., “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. of Quant. Chem. 43, 27–36 (1992).Google Scholar
[9] Heflin, J. R., Cai, Y. M., and Carito, A. F., “Dispersion measurements of electric-fieldinduced second-harmonic generation and third-harmonic generation in conjugated linear chains,” J. Opt. Soc. Am. B 8, 2132–2147 (1991).Google Scholar
[10] Heflin, J. R., Rodenberger, D. C., Shi, R. F., Wu, M., Wang, N. Q., Cai, Y. M., and Garito, A. F., “Experimental observation of enhanced nonresonant nonlinear optical responses from optically pumped electronic excited states,” Phys. Rev. A, 45, R4233–R4236 (1992).Google Scholar
[11] Pierce, B. M., “A theoretical analysis of the third-order nonlinear optical properties of linear cyanines and polyenes,” in Nonlinear Optical Properties of Organic Materials IV Proc. SPIE 1560, 148–161 (1991).Google Scholar
[12] Wu, J. W., Heflin, J. R., Norwood, R. A., Wong, K. Y., Zamani-Khamiri, O., Carito, A. F., Kalyanaraman, P., and Sounik, J., “Nonlinear-optical processes in lower-dimensional conjugated structures,” J. Opt. Soc. Am. B 6, 707–720 (1989).Google Scholar
[13] M.Kuzyk, C., Sohn, J. E., and Dirk, C. W., “Mechanisms of quadratic electro-optic modulation of dye doped polymer systems,” J. Opt. Soc. Am. B 7, 842–858 (1990).Google Scholar