Metamaterials offer unprecedented flexibility for manipulating the optical properties of matter, including the ability to access negative index1, 2, 3, 4, ultrahigh index5 and chiral optical properties6, 7, 8. Recently, metamaterials with near-zero refractive index have attracted much attention9, 10, 11, 12, 13. Light inside such materials experiences no spatial phase change and extremely large phase velocity, properties that can be applied for realizing directional emission14, 15, 16, tunnelling waveguides17, large-area single-mode devices18 and electromagnetic cloaks19. However, at optical frequencies, the previously demonstrated zero- or negative-refractive-index metamaterials have required the use of metallic inclusions, leading to large ohmic loss, a serious impediment to device applications20, 21. Here, we experimentally demonstrate an impedance-matched zero-index metamaterial at optical frequencies based on purely dielectric constituents. Formed from stacked silicon-rod unit cells, the metamaterial has a nearly isotropic low-index response for transverse-magnetic polarized light, leading to angular selectivity of transmission and directive emission from quantum dots placed within the material.
At a glance
- Experimental verification of a negative index of refraction. Science 292, 77–79 (2001). , &
- Experimental demonstration of near-infrared negative-index metamaterials. Phys. Rev. Lett. 95, 137404 (2005). et al.
- Negative index of refraction in optical metamaterials. Opt. Lett. 30, 3356–3358 (2005). et al.
- Three-dimensional optical metamaterial with a negative refractive index. Nature 455, 376–379 (2008). et al.
- A terahertz metamaterial with unnaturally high refractive index. Nature 470, 369–373 (2011). et al.
- Circular dichroism of planar chiral magnetic metamaterials. Opt. Lett. 32, 856–858 (2007). , , &
- Giant optical gyrotropy due to electromagnetic coupling. Appl. Phys. Lett. 90, 223113 (2007). , , , &
- Negative refractive index in chiral metamaterials. Phys. Rev. Lett. 102, 023901 (2009). et al.
- Experimental demonstration of electromagnetic tunneling through an epsilon-near-zero metamaterial at microwave frequencies. Phys. Rev. Lett. 100, 023903 (2008). et al.
- Dirac cones induced by accidental degeneracy in photonic crystals and zero-refractive-index materials. Nature Mater. 10, 582–586 (2011). , , , &
- Low-loss impedance-matched optical metamaterials with zero-phase delay. ACS Nano 6, 4475–4482 (2012). et al.
- Experimental verification of n = 0 structures for visible light. Phys. Rev. Lett. 110, 013902 (2013). , , , &
- Funneling light through a subwavelength aperture with epsilon-near-zero materials. Phys. Rev. Lett. 107, 133901 (2011). et al.
- A metamaterial for directive emission. Phys. Rev. Lett. 89, 213902 (2002). , , , &
- Propagation in and scattering from a matched metamaterial having a zero index of refraction. Phys. Rev. E 70, 046608 (2004).
- Epsilon-near-zero metamaterials and electromagnetic sources: tailoring the radiation phase pattern. Phys. Rev. B 75, 155410 (2007). , &
- Tunneling of electromagnetic energy through subwavelength channels and bends using ε-near-zero materials. Phys. Rev. Lett. 97, 157403 (2006). &
- Enabling single-mode behavior over large areas with photonic Dirac cones. Proc. Natl Acad. Sci. USA 109, 9761–9765 (2012). , &
- Super-reflection and cloaking based on zero index metamaterial. Appl. Phys. Lett. 96, 101109 (2010). , &
- Low-loss plasmonic metamaterials. Science 331, 290–291 (2011). &
- Past achievements and future challenges in the development of three-dimensional photonic metamaterials. Nature Photon. 5, 523–530 (2011). &
- The electrical constants of a material loaded with spherical particles. Proc. Inst. Elec. Eng. Part 3 94, 65–68 (1947).
- Photonic band-gap effects and magnetic activity in dielectric composites. J. Phys. Condens. Matter 14, 4035–4044 (2002). &
- Mie resonance-based dielectric metamaterials. Mater. Today 12, 60–69 (2009). , , &
- Experimental demonstration of isotropic negative permeability in a three-dimensional dielectric composite. Phys. Rev. Lett. 101, 027402 (2008). et al.
- Magnetic light. Sci. Rep. 2, 492 (2012). , , , &
- A new dielectric metamaterial building block with a strong magnetic response in the sub-1.5-micrometer region: silicon colloid nanocavities. Adv. Mater. 24, 5934–5938 (2012). , , &
- Experimental observation of left-handed behavior in an array of standard dielectric resonators. Phys. Rev. Lett. 98, 157403 (2007). et al.
- Compact dielectric particles as a building block for low-loss magnetic metamaterials. Phys. Rev. Lett. 100, 207401 (2008). &
- Realizing optical magnetism from dielectric metamaterials. Phys. Rev. Lett. 108, 097402 (2012). et al.
- Two-dimensional gas of massless Dirac fermions in graphene. Nature 438, 197–200 (2005). et al.
- Effective parameters of metamaterials: a rigorous homogenization theory via Whitney interpolation. J. Opt. Soc. Am. B 28, 577–586 (2011).
- Effective medium theory for magnetodielectric composites: beyond the long-wavelength limit. Phys. Rev. B 74, 085111 (2006). , , &
- Robust method to retrieve the constitutive effective parameters of metamaterials. Phys. Rev. E 70, 016608 (2004). , &
- Electromagnetic parameter retrieval from inhomogeneous metamaterials. Phys. Rev. E 71, 036617 (2005). , , &
- Supplementary information (1.16 MB)