The realization of slow light with ultra-flat dispersion in hybrid photonic crystal (HPhC) waveguide is systematically investigated. Metal strips have been introduced to the photonic crystal (PhC) waveguide. The dispersion of the odd mode is commendably flattened in the leaky region. Ultra-flat-band slow light with nearly constant average group indices of 192 over 2 nm (i.e., 330 GHz) bandwidth is achieved. Flexible tuning for the ultra-high group index can also be achieved while keeping the normalized delay-bandwidth product fairly high. The introduction of the metal strips is further demonstrated to help reduce the azimuthal angle of the farfield and provide a high coupling efficiency.
2. Taskmakidis, K. L., A. D. Boardman, and O. Hess, "`Trapped’ rainbow storage of light in metamaterials," Nature, Vol. 450, 397-401, 2007.
3. Taskmakidis, K. L., T. W. Pickering, J. M. Hamm, A. F. Page, and O. Hess, "Completely stopped and dispersionless light in plasmonic waveguides," Phys. Rev. Lett., Vol. 112, 167401-1-167401-5, 2013.
4. Pickering, T., J. M. Hamm, J. F. Page, S.Wuestner, and O. Hess, "Cavity-free plasmonic nanolasing enabled by dispersionless stopped light," Nat Comm., Vol. 5, 4972, 2014.
5. Rao, V. S. C. M. and S. Hughes, "Single quantum-dot Purcell factor and Beta factor in a photonic crystal waveguide," Phys. Rev. B, Vol. 75, 205437, 2007.
6. Yao, P., C. V. Vlack, A. Reza, M. Petterson, M. M. Dignam, and S. Hughes, "Ultrahigh Purcell factors and Lamb shifts in slow-light metamaterial waveguides," Phys. Rev. B, Vol. 80, 195106, 2009.
7. Ek, S., E. Semenova, P. Lunnemann, K. Yvind, and J. Mork, "Enhanced gain in photonic crystal amplifiers," IEEE ICTON, 1-4, 2012.
8. Tran, N. V. Q., S. Combrie, and A. D. Rossi, "Directive emission from high-Q photonic crystal cavities through band folding," Phys. Rev. B, Vol. 79, 041101, 2009.
9. Benyatto, T., E. Gerelli, L. Milord, C. Jamois, A. Harouri, C. Chevalier, C. Seassal, A. Belarouci, X. Letartre, and P. Viktorovitch, "Slow Bloch mode cavity for optical trapping," IEEE ICTON, 1-5, 2013.
10. Brown, E. R. and O. B. McMabon, "High zenithal directivity from a dipole antenna on a photonic crystal," Appl. Phys. Lett., Vol. 68, 1300-1302, 1996.
11. Temelkuran, B., M. Bayindir, E. ozbay, R. Riswas, M. M. Sigalas, G. Tuttle, and K. M. Ho, "Photonic crystal-based resonant antenna with a very high directivity," Appl. Phys. Lett., Vol. 87, 602-605, 2000.
12. Tevenot, M., C. Cheype, A. Reineix, and B. Jecko, "Directive photonic-bandgap antennas," IEEE Trans. on Micr. Theo. and Tech., Vol. 47, 2115-2122, 1999.
13. Sa, Z. H., Y. Poo, R. X. Wu, and C. Xiao, "An implementation of directional antenna by self-biased magnetic photonic crystal," Appl. Phys. A, Vol. 117, No. 2, 427-431, Springer, 2014.
14. Hu, J. and C. R. Menyuk, "Understanding leaky modes: Slab waveguide revisited," Advs. in Optics and Photon., Vol. 1, 58-106, 2009.
15. Baba, T. and D. Mori, "Slow light engineering in photonic crystal," J. Phys. D: Appl. Phys., Vol. 40, 2659-2665, 2007.
16. Krauss, T. F., "Slow light in photonic crystal waveguides," J. Phys. D: Appl. Phys., Vol. 40, 2666-2670, 2008.
17. Liang, J., L. Ren, M. Yun, X. Han, and X. Wang, "Wideband ultraflat slow light with large group index in a W1 photonic crystal waveguide," Appl. Phys. Lett., Vol. 110, 063103, 2011.
18. Frandsen, L. H., A. V. Lavrinenko, J. Fage-Pedersen, and P. I. Borel, "Photonic crystal waveguides with semi-low light and tailored dispersion properties," Opt. Express, Vol. 14, 9444-9450, 2006.
19. Mann, N., S. Combrie, M. Patterson, A. D. Rossi, and S. Hughes, "Reducing disorder-induced losses for slow light photonic crystal waveguides through Bloch mode engineering," Opt. Lett., Vol. 38, 4244-4247, 2013.
20. How, J., D. Gao, H. Wu, R. Hao, and Z. Zhou, "Flat band slow light in symmetric line defect photonic crystal waveguides," IEEE Photon. Tech. Lett., Vol. 21, 1571-1573, 2009.
21. Baba, T., T. Kawasaki, H. Sasaki, J. Adachi, and D. Mori, "Large delay-bandwidth product and tuning of slow light pulse in photonic crystal coupled waveguide," Opt. Express, Vol. 16, 9245-9253, 2008.
22. Xu, Y., L. Xiang, E. Cassan, D. Gao, and X. Zhang, "Slow light in an alternative row of ellipse-hole photonic crystal waveguide," Appl. Opt., Vol. 52, 1155-1160, 2013.
23. Saynatjoki, A., M. Mulot, J. Ahopelto, and H. Lipsanen, "Dispersion engineering of photonic crystal waveguides with ring-shaped holes," Opt. Express, Vol. 15, 8323-8328, 2007.
24. Ma, J. and C. Jiang, "Demonstration of ultraslow modes in asymmetric line-defect photonic crystal waveguides," IEEE Photon. Tech. Lett., Vol. 20, No. 14, 1237-1239, 2008.
25. Ma, J. and C. Jiang, "Flatband slow light in asymmetric line-defect photonic crystal waveguide featuring low group velocity and dispersion," IEEE Journal of Quant. Electron., Vol. 44, No. 8, 763-769, 2008.
26. Hao, R., E. Cassan, H. Kurt, X. L. Roux, D. Marris-Morini, L. Vivien, H. Wu, Z. Zhou, and X. Zhang, "Novel slow light waveguide with controllable delay-bandwidth product and ultra-low dispersion," Opt. Express, Vol. 18, 5942-5950, 2010.
27. Hao, R., E. Cassan, X. L. Roux, D. Gao, V. D. Khanh, L. Vivien, H. D. Marris-Morini, and X. Zhang, "Improvement of delay-bandwidth product in photonic crystal slow-light waveguides," Opt. Express, Vol. 18, 16309-16319, 2010.
28. Johnson, P. and R. Christy, "Optical constants of noble metals," Phys. Rev. B, Vol. 6, 4370-4379, 1972.
29. Palik, E. D., Handbook of Optical Constants of Solids, Academic Press, 1998.