G. Dolling, C. Enkrich, M. Wegener, C. M. Soukoulis, S. Linden, "Simultaneous negative phase and group velocity
of light in a metamaterial," Science 312, 892-894 (2006).

J. Zhou, L. Zhang, G. Tuttle, T. Koschnny, C. M. Soukoulis, "Negative
index materials using simple short wire pairs," Phys.
Rev. B 73, 041101 (2006).

G. Dolling, C. Enkrich, M. Wegener, J. F. Zhou, C. M. Soukoulis, "Cut-wire pairs and plate pairs as magnetic
atoms for optical metamaterials," Opt. Lett. 30, 3198-3200 (2005).

V. M. Shalaev, W. S. Cai, U. K. Chettiar, H. K. Yuan, A. K. Sarychev, V. P. Drachev, A. V. Kildishev, "Negative index of refraction in optical
metamaterials," Opt. Lett. 30, 3356-3358 (2005).

S. Zhang, W. J. Fan, N. C. Panoiu, K. J. Malloy, R. M. Osgood, S. R. J. Brueck, "Experimental demonstration of near-infrared negative-index
metamaterials," Phys. Rev. Lett. 95, 137404 (2005).

J. Huangfu, L. Ran, H. Chen, X. Zhang, K. Chen, T. M. Grzegorczyk, J. A. Kong, "Experimental confirmation of
negative refractive index of a metamaterial composed of Omega-like metallic
patterns," Appl. Phys. Lett. 84, 1537-1539 (2004).

H. Chen, L. Ran, J. Huangfu, X. Zhang, K. Chen, T. M. Grzegorczyk, J. A. Kong, "Left-handed material composed
of only S-shaped resonators," Phys. Rev. E 70, 057605 (2004).

A. F. Starr, P. M. Rye, D. R. Smith, S. Nemat-Nasser, "Fabrication and characterization of a negative-index
composite metamaterial," Phys. Rev. B 70, 113102 (2004).

A. Alu, N. Engheta, "Guided modes in a waveguide filled with a pair of single-negative
(SNG), double-negative (DNG), and/or double-positive (DPS) layers," IEEE Trans. Microwave Theory Tech. 52, 199-210 (2004).

I. V. Shadrivov, A. A. Sukhorukov, Y. S. Kivshar, "Guided modes in negative-refractive-index
waveguides," Phys. Rev. E 67, 057602 (2003).

B.-l. Wu, T. M. Grzegorczyk, Y. Zhang, J. A. Kong, "Guided
modes with imaginary, transverse wave number in a slab waveguide with negative
permittivity and permeability," J. Appl. Phys. 93, 9386-9388 (2003).

A. C. Peacock, N. G. R. Broderick, "Guided modes in channel waveguides with
a negative index of refraction," Opt. Exp. 11, 2502-2510 (2003).

K. Halterman, J. M. Elson, P. L. Overfelt, "Characteristics of bound modes in coupled
dielectric waveguides containing negative index media," Opt.
Exp. 11, 521-524 (2003).

R. A. Shelby, D. R. Smith, S. Schultz, "Experimental verification of a negative
index of refraction," Science 242, 77-79 (2001).

D. R. Smith, N. Kroll, "Negative refractive index in left-handed materials," Phys. Rev. Lett. 85, 2433-2436 (2000).

J. B. Pendry, "Negative refraction makes a perfect lens," Phys. Rev. Lett. 85, 3966-3969 (2000).

W. Streifer, M. Osinski, A. Hardy, "Reformulation of the coupledmode theory of multiwaveguide
systems," J. Lightw. Technol. 5, 1-4 (1987).

H. A. Haus, W. P. Huang, S. Kawakami, N. A. Whitaker, "Coupled-mode theory of optical waveguides," J. Lightw. Technol. 5, 16-23 (1987).

A. W. Snyder, A. Ankiewicz, "Fibre couplers composed of unequal cores," Electron. Lett. 22, 1237-1238 (1986).

A. Hardy, W. Streifer, "Coupled mode theory of parallel waveguides," J. Lightw. Technol. 3, 1135-1146 (1985).

V. G. Veselago, "The electrodynamics of substances with simultaneously
negative values of $\epsilon$ and $\mu$," Sov. Phys.
Usp. 10, 509-514 (1968).

J. Huangfu, L. Ran, H. Chen, X. Zhang, K. Chen, T. M. Grzegorczyk, J. A. Kong, "Experimental confirmation of
negative refractive index of a metamaterial composed of Omega-like metallic
patterns," Appl. Phys. Lett. 84, 1537-1539 (2004).

A. W. Snyder, A. Ankiewicz, "Fibre couplers composed of unequal cores," Electron. Lett. 22, 1237-1238 (1986).

A. Alu, N. Engheta, "Guided modes in a waveguide filled with a pair of single-negative
(SNG), double-negative (DNG), and/or double-positive (DPS) layers," IEEE Trans. Microwave Theory Tech. 52, 199-210 (2004).

B.-l. Wu, T. M. Grzegorczyk, Y. Zhang, J. A. Kong, "Guided
modes with imaginary, transverse wave number in a slab waveguide with negative
permittivity and permeability," J. Appl. Phys. 93, 9386-9388 (2003).

A. Hardy, W. Streifer, "Coupled mode theory of parallel waveguides," J. Lightw. Technol. 3, 1135-1146 (1985).

H. A. Haus, W. P. Huang, S. Kawakami, N. A. Whitaker, "Coupled-mode theory of optical waveguides," J. Lightw. Technol. 5, 16-23 (1987).

W. Streifer, M. Osinski, A. Hardy, "Reformulation of the coupledmode theory of multiwaveguide
systems," J. Lightw. Technol. 5, 1-4 (1987).

K. Halterman, J. M. Elson, P. L. Overfelt, "Characteristics of bound modes in coupled
dielectric waveguides containing negative index media," Opt.
Exp. 11, 521-524 (2003).

A. C. Peacock, N. G. R. Broderick, "Guided modes in channel waveguides with
a negative index of refraction," Opt. Exp. 11, 2502-2510 (2003).

G. Dolling, C. Enkrich, M. Wegener, C. M. Soukoulis, S. Linden, "Negative-index metamaterial at 780 nm wavelength," Opt. Lett. 32, 53-55 (2007).

G. Dolling, C. Enkrich, M. Wegener, J. F. Zhou, C. M. Soukoulis, "Cut-wire pairs and plate pairs as magnetic
atoms for optical metamaterials," Opt. Lett. 30, 3198-3200 (2005).

V. M. Shalaev, W. S. Cai, U. K. Chettiar, H. K. Yuan, A. K. Sarychev, V. P. Drachev, A. V. Kildishev, "Negative index of refraction in optical
metamaterials," Opt. Lett. 30, 3356-3358 (2005).

H. A. Haus, W. P. Huang, A. W. Snyder, "Coupled-mode formulations," Opt. Lett. 14, 1222-1224 (1989).

J. Zhou, L. Zhang, G. Tuttle, T. Koschnny, C. M. Soukoulis, "Negative
index materials using simple short wire pairs," Phys.
Rev. B 73, 041101 (2006).

A. F. Starr, P. M. Rye, D. R. Smith, S. Nemat-Nasser, "Fabrication and characterization of a negative-index
composite metamaterial," Phys. Rev. B 70, 113102 (2004).

I. V. Shadrivov, A. A. Sukhorukov, Y. S. Kivshar, "Guided modes in negative-refractive-index
waveguides," Phys. Rev. E 67, 057602 (2003).

H. Chen, L. Ran, J. Huangfu, X. Zhang, K. Chen, T. M. Grzegorczyk, J. A. Kong, "Left-handed material composed
of only S-shaped resonators," Phys. Rev. E 70, 057605 (2004).

D. R. Smith, N. Kroll, "Negative refractive index in left-handed materials," Phys. Rev. Lett. 85, 2433-2436 (2000).

J. B. Pendry, "Negative refraction makes a perfect lens," Phys. Rev. Lett. 85, 3966-3969 (2000).

S. Zhang, W. J. Fan, N. C. Panoiu, K. J. Malloy, R. M. Osgood, S. R. J. Brueck, "Experimental demonstration of near-infrared negative-index
metamaterials," Phys. Rev. Lett. 95, 137404 (2005).

G. Dolling, C. Enkrich, M. Wegener, C. M. Soukoulis, S. Linden, "Simultaneous negative phase and group velocity
of light in a metamaterial," Science 312, 892-894 (2006).

R. A. Shelby, D. R. Smith, S. Schultz, "Experimental verification of a negative
index of refraction," Science 242, 77-79 (2001).

V. G. Veselago, "The electrodynamics of substances with simultaneously
negative values of $\epsilon$ and $\mu$," Sov. Phys.
Usp. 10, 509-514 (1968).

A. Alu, N. Engheta, "Anomalous mode coupling in guided-wave structures containing
metamaterials with negative permittivity and permeability," Proc. IEEE Nanotechnology (2002) pp. 233-234.