[1] Siegman A E 1986 Laser (California: Mill Valley)
[2] Sargent III M, Scully M O, Lamb W E 1974 Laser Physics (Mass: Addison-Wesly Reading)
[3] Yariv A 1997 Optical Electronics in Morden Communications (New York: Oxford Univ Press)
[4] Einstein A 1917 Phys. Z. 18 121
[5] Lamb W E 1964 Phys. Rev. A 134 1429
[6] Marcuse D 1980 Principles of Quantum Electronics (New York: Academic Press)
[7] Xiao S M, Drachev V P, Kildishev A V, Ni X J, Chettiar U K, Yuan H K, Shalaev V M 2010 Nature 466 735
[8] Fang A, Koschny T, Wegener M, Soukoulis C M 2009 Phys. Rev. B 78 241104
[9] Sivan Y, Xiao S M, Chettiar U K, Kildishev A V, Shalaev V M 2010 Optics Express 17 24060
[10] Fang A, Koschny T, Soukoulis C M 2010 Phys. Rev. B 82 121102
[11] Wuestner S, Pusch A, Tsakmakidis K L, Hamm J M, Hess O 2010 Phys. Rev. Lett. 105 127401
[12] Fang A, Huang Z X, Koschny T, Soukoulis C M 2012 Photonics and Nanostructures-Fundementals and Applications 10 276
[13] Fang A, Huang Z X, Koschny T, Soukoulis C M 2012 Optics Express 19 12688
[14] Hawkins R J, Kallman J S 1994 Opt Quantum Electron 26 207
[15] Hagness S C, Joseph R M, Taflove A 1996 Radio Sci 31 931
[16] Nagra A S, York R A 1998 IEEE Transaction on Antennas and propagation 46 334
[17] Fang A, Koschny T, Soukoulis C M 2010 Journal of Optics 12 024013
[18] Florescu L, Busch K, John S 2002 Optical B 19 2215
[19] Taflove A 1995 Computational Electrodynamics: The Finite Difference Time Domain Method (Norwood, MA: Artech House)