C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

J. H. Andrews, J. D. V. Khaydarov, K. D. Singer, D. L. Hull, and K. C. Chuang, “Characterization of excited states of centrosymmetric and noncentrosymmetric squaraines by third harmonic spectral dispersion,” J. Opt. Soc. Am. B 12, 2360 (1995).

C. Poga, T. M. Brown, M. G. Kuzyk, and C. W. Dirk, “Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy,” J. Opt. Soc. Am. B 12, 531 (1995).

C. Poga, M. G. Kuzyk, and C. W. Dirk, “Quadratic electroabsorption studies of third-order susceptibility mechanisms in dye-doped polymers,” J. Opt. Soc. Am. B 11, 80 (1994).

Y. Z. Yu, R. F. Shi, A. F. Garito, and C. H. Grossman, “Origin of negative χ^{(3)} in squaraines: experimental observation of two-photon states,” Opt. Lett. 19, 786 (1994).

K. Zimmerman, F. Ghebremichael, and M. G. Kuzyk, “Electric-field-induced polarization current studies in guest–host polymers,” J. Appl. Phys. 75, 1270 (1994).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

C. W. Dirk, L.-T. Cheng, and M. G. Kuzyk, “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. Quantum Chem. 43, 27 (1992).

C. W. Dirk and M. G. Kuzyk, “Damping corrections and the calculation of optical nonlinearities in organic molecules,” Phys. Rev. B 41, 1636 (1990).

M. G. Kuzyk and C. W. Dirk, “Effects of centrosymmetry on the nonresonant electronic third-order nonlinear optical susceptibility,” Phys. Rev. A 41, 5098 (1990).

M. G. Kuzyk, J. E. Sohn, and C. W. Dirk, “Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems,” J. Opt. Soc. Am. B 7, 842 (1990).

C. W. Dirk and M. G. Kuzyk, “Squarylium dye-doped polymer systems as quadratic electrooptic materials,” Chem. Mater. 2, 4 (1990).

J. C. Luong, N. F. Borrelli, and A. R. Olszewski, “Quadratic electro-optical characterization of molecular nonlinear optical materials,” Mater. Res. Soc. Symp. Proc. 109, 251 (1988).

R. W. Bigelow and H. Freund, “An MNDO and CNDO/S(S+DES CI) study on the structural and electronic properties of a model squaraine dye and related cyanine,” Chem. Phys. 107, 159 (1986).

B. J. Orr and J. F. Ward, “Perturbation theory of the non-linear optical polarization of an isolated system,” Mol. Phys. 20, 513 (1971).

R. W. Bigelow and H. Freund, “An MNDO and CNDO/S(S+DES CI) study on the structural and electronic properties of a model squaraine dye and related cyanine,” Chem. Phys. 107, 159 (1986).

J. C. Luong, N. F. Borrelli, and A. R. Olszewski, “Quadratic electro-optical characterization of molecular nonlinear optical materials,” Mater. Res. Soc. Symp. Proc. 109, 251 (1988).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. W. Dirk, L.-T. Cheng, and M. G. Kuzyk, “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. Quantum Chem. 43, 27 (1992).

C. Poga, T. M. Brown, M. G. Kuzyk, and C. W. Dirk, “Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy,” J. Opt. Soc. Am. B 12, 531 (1995).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. Poga, M. G. Kuzyk, and C. W. Dirk, “Quadratic electroabsorption studies of third-order susceptibility mechanisms in dye-doped polymers,” J. Opt. Soc. Am. B 11, 80 (1994).

C. W. Dirk, L.-T. Cheng, and M. G. Kuzyk, “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. Quantum Chem. 43, 27 (1992).

M. G. Kuzyk, J. E. Sohn, and C. W. Dirk, “Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems,” J. Opt. Soc. Am. B 7, 842 (1990).

C. W. Dirk and M. G. Kuzyk, “Squarylium dye-doped polymer systems as quadratic electrooptic materials,” Chem. Mater. 2, 4 (1990).

M. G. Kuzyk and C. W. Dirk, “Effects of centrosymmetry on the nonresonant electronic third-order nonlinear optical susceptibility,” Phys. Rev. A 41, 5098 (1990).

C. W. Dirk and M. G. Kuzyk, “Damping corrections and the calculation of optical nonlinearities in organic molecules,” Phys. Rev. B 41, 1636 (1990).

R. W. Bigelow and H. Freund, “An MNDO and CNDO/S(S+DES CI) study on the structural and electronic properties of a model squaraine dye and related cyanine,” Chem. Phys. 107, 159 (1986).

Y. Z. Yu, R. F. Shi, A. F. Garito, and C. H. Grossman, “Origin of negative χ^{(3)} in squaraines: experimental observation of two-photon states,” Opt. Lett. 19, 786 (1994).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

K. Zimmerman, F. Ghebremichael, and M. G. Kuzyk, “Electric-field-induced polarization current studies in guest–host polymers,” J. Appl. Phys. 75, 1270 (1994).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. Poga, T. M. Brown, M. G. Kuzyk, and C. W. Dirk, “Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy,” J. Opt. Soc. Am. B 12, 531 (1995).

K. Zimmerman, F. Ghebremichael, and M. G. Kuzyk, “Electric-field-induced polarization current studies in guest–host polymers,” J. Appl. Phys. 75, 1270 (1994).

C. Poga, M. G. Kuzyk, and C. W. Dirk, “Quadratic electroabsorption studies of third-order susceptibility mechanisms in dye-doped polymers,” J. Opt. Soc. Am. B 11, 80 (1994).

C. W. Dirk, L.-T. Cheng, and M. G. Kuzyk, “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. Quantum Chem. 43, 27 (1992).

C. W. Dirk and M. G. Kuzyk, “Damping corrections and the calculation of optical nonlinearities in organic molecules,” Phys. Rev. B 41, 1636 (1990).

M. G. Kuzyk and C. W. Dirk, “Effects of centrosymmetry on the nonresonant electronic third-order nonlinear optical susceptibility,” Phys. Rev. A 41, 5098 (1990).

C. W. Dirk and M. G. Kuzyk, “Squarylium dye-doped polymer systems as quadratic electrooptic materials,” Chem. Mater. 2, 4 (1990).

M. G. Kuzyk, J. E. Sohn, and C. W. Dirk, “Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems,” J. Opt. Soc. Am. B 7, 842 (1990).

K. D. Singer, M. G. Kuzyk, and J. E. Sohn, “Second-order nonlinear-optical processes in orientationally ordered materials: relationship between molecular and macroscopic properties,” J. Opt. Soc. Am. B 4, 968 (1987).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

J. C. Luong, N. F. Borrelli, and A. R. Olszewski, “Quadratic electro-optical characterization of molecular nonlinear optical materials,” Mater. Res. Soc. Symp. Proc. 109, 251 (1988).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

J. C. Luong, N. F. Borrelli, and A. R. Olszewski, “Quadratic electro-optical characterization of molecular nonlinear optical materials,” Mater. Res. Soc. Symp. Proc. 109, 251 (1988).

B. J. Orr and J. F. Ward, “Perturbation theory of the non-linear optical polarization of an isolated system,” Mol. Phys. 20, 513 (1971).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

C. Poga, T. M. Brown, M. G. Kuzyk, and C. W. Dirk, “Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy,” J. Opt. Soc. Am. B 12, 531 (1995).

C. Poga, M. G. Kuzyk, and C. W. Dirk, “Quadratic electroabsorption studies of third-order susceptibility mechanisms in dye-doped polymers,” J. Opt. Soc. Am. B 11, 80 (1994).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

Y. Z. Yu, R. F. Shi, A. F. Garito, and C. H. Grossman, “Origin of negative χ^{(3)} in squaraines: experimental observation of two-photon states,” Opt. Lett. 19, 786 (1994).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

J. H. Andrews, J. D. V. Khaydarov, K. D. Singer, D. L. Hull, and K. C. Chuang, “Characterization of excited states of centrosymmetric and noncentrosymmetric squaraines by third harmonic spectral dispersion,” J. Opt. Soc. Am. B 12, 2360 (1995).

K. D. Singer, M. G. Kuzyk, and J. E. Sohn, “Second-order nonlinear-optical processes in orientationally ordered materials: relationship between molecular and macroscopic properties,” J. Opt. Soc. Am. B 4, 968 (1987).

M. G. Kuzyk, J. E. Sohn, and C. W. Dirk, “Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems,” J. Opt. Soc. Am. B 7, 842 (1990).

K. D. Singer, M. G. Kuzyk, and J. E. Sohn, “Second-order nonlinear-optical processes in orientationally ordered materials: relationship between molecular and macroscopic properties,” J. Opt. Soc. Am. B 4, 968 (1987).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

B. J. Orr and J. F. Ward, “Perturbation theory of the non-linear optical polarization of an isolated system,” Mol. Phys. 20, 513 (1971).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

K. Zimmerman, F. Ghebremichael, and M. G. Kuzyk, “Electric-field-induced polarization current studies in guest–host polymers,” J. Appl. Phys. 75, 1270 (1994).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

C. W. Dirk and M. G. Kuzyk, “Squarylium dye-doped polymer systems as quadratic electrooptic materials,” Chem. Mater. 2, 4 (1990).

R. W. Bigelow and H. Freund, “An MNDO and CNDO/S(S+DES CI) study on the structural and electronic properties of a model squaraine dye and related cyanine,” Chem. Phys. 107, 159 (1986).

C. W. Dirk, L.-T. Cheng, and M. G. Kuzyk, “A simplified three-level model describing the molecular third-order nonlinear optical susceptibility,” Int. J. Quantum Chem. 43, 27 (1992).

C. W. Dirk, W. C. Herndon, F. Cervantes-Lee, H. Selnau, S. Martinez, P. Kalamegham, A. Tan, G. Campos, M. Velez, J. Zyss, I. Ledoux, and L. Cheng, “Squarylium dyes: structural factors pertaining to the negative third-order nonlinear optical response,” J. Am. Chem. Soc. 117, 2214 (1995).

K. Zimmerman, F. Ghebremichael, and M. G. Kuzyk, “Electric-field-induced polarization current studies in guest–host polymers,” J. Appl. Phys. 75, 1270 (1994).

K. D. Singer, M. G. Kuzyk, and J. E. Sohn, “Second-order nonlinear-optical processes in orientationally ordered materials: relationship between molecular and macroscopic properties,” J. Opt. Soc. Am. B 4, 968 (1987).

M. G. Kuzyk, J. E. Sohn, and C. W. Dirk, “Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems,” J. Opt. Soc. Am. B 7, 842 (1990).

J. H. Andrews, J. D. V. Khaydarov, K. D. Singer, D. L. Hull, and K. C. Chuang, “Characterization of excited states of centrosymmetric and noncentrosymmetric squaraines by third harmonic spectral dispersion,” J. Opt. Soc. Am. B 12, 2360 (1995).

C. Poga, T. M. Brown, M. G. Kuzyk, and C. W. Dirk, “Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy,” J. Opt. Soc. Am. B 12, 531 (1995).

C. Poga, M. G. Kuzyk, and C. W. Dirk, “Quadratic electroabsorption studies of third-order susceptibility mechanisms in dye-doped polymers,” J. Opt. Soc. Am. B 11, 80 (1994).

J. C. Luong, N. F. Borrelli, and A. R. Olszewski, “Quadratic electro-optical characterization of molecular nonlinear optical materials,” Mater. Res. Soc. Symp. Proc. 109, 251 (1988).

B. J. Orr and J. F. Ward, “Perturbation theory of the non-linear optical polarization of an isolated system,” Mol. Phys. 20, 513 (1971).

Q. L. Zhou, R. F. Shi, O. Zamani-Khamari, and A. F. Garito, “Negative third-order optical responses in squaraines,” Nonlinear Opt. 6, 145 (1993).

M. G. Kuzyk and C. W. Dirk, “Effects of centrosymmetry on the nonresonant electronic third-order nonlinear optical susceptibility,” Phys. Rev. A 41, 5098 (1990).

C. W. Dirk and M. G. Kuzyk, “Damping corrections and the calculation of optical nonlinearities in organic molecules,” Phys. Rev. B 41, 1636 (1990).

S. Marder, J. W. Perry, G. Bourhill, C. B. Gorman, B. G. Tiemann, and K. Mansour, “Relation between bond-length alternation and second electronic hyperpolarizability of conjugated organic molecules,” Science 261, 186 (1993).

J. Zyss, “Nonlinear organic materials for integrated optics: a review,” J. Molec. Electron. 1, 25 (1985).

C. Poga, “Mechanisms of the third-order nonlinear optical response in dye-doped polymers,” Ph.D. dissertation (Washington State University, Pullman, Wash., 1994).

R. W. Boyd, Nonlinear Optics (Academic, San Diego, Calif., 1992).

Y. R. Shen, Principles of Nonlinear Optics (Wiley-Interscience, New York, 1984).

M. G. Kuzyk and C. Poga, “Quadratic electro-optics of guest–host polymers,” in Molecular Nonlinear Optics: Materials, Physics, and Devices, J. Zyss, ed. (Academic, San Diego, Calif., 1993), pp. 299–337.