Giant photonic spin Hall effect in momentum space in a structured metamaterial with spatially varying birefringence

The photonic spin Hall effect (SHE) in the reflection and refraction at an interface is very weak because of the weak spin-orbit interaction. Here, we report the observation of a giant photonic SHE in a dielectric-based metamaterial. The metamaterial is structured to create a coordinate-dependent, geometric Pancharatnam–Berry phase that results in an SHE with a spin-dependent splitting in momentum space. It is unlike the SHE that occurs in real space in the reflection and refraction at an interface, which results from the momentum-dependent gradient of the geometric Rytov–Vladimirskii–Berry phase. We theorize a unified description of the photonic SHE based on the two types of geometric phase gradient, and we experimentally measure the giant spin-dependent shift of the beam centroid produced by the metamaterial at a visible wavelength. Our results suggest that the structured metamaterial offers a potential method of manipulating spin-polarized photons and the orbital angular momentum of light and thus enables applications in spin-controlled nanophotonics. A giant photonic spin Hall effect (SHE) has been predicted and experimentally observed in a dielectric metamaterial by scientists in China. The conventional SHE that occurs when light is reflected or refracted at an interface is inherently weak due to the weak spin–orbit interaction. Now, researchers at Hunan University, Hengyang Normal University and Shenzhen University have theoretically predicted and experimentally confirmed a giant SHE in a metamaterial structured to produce the Pancharatnam–Berry phase in one dimension and having a spatially varying birefringence. Unlike the tiny real-space shift induced by the Rytov–Vladimirskii–Berry phase gradient, the giant SHE occurs in momentum space and is sufficiently large to be observed directly. Such metamaterials could potentially be used to manipulate spin-polarized photons and the orbital angular momentum of light, enabling applications in spin-controlled nanophotonics.

[1]  S. Wen,et al.  Generation of cylindrical vector vortex beams by two cascaded metasurfaces. , 2014, Optics express.

[2]  K. Bliokh,et al.  Conservation of angular momentum, transverse shift, and spin Hall effect in reflection and refraction of an electromagnetic wave packet. , 2006, Physical review letters.

[3]  Y. Shimotsuma,et al.  Self-organized nanogratings in glass irradiated by ultrashort light pulses. , 2003, Physical review letters.

[4]  Peter G. Kazansky,et al.  Radially polarized optical vortex converter created by femtosecond laser nanostructuring of glass , 2011 .

[5]  Qiaofeng Tan,et al.  Dual-polarity plasmonic metalens for visible light , 2012, Nature Communications.

[6]  Erez Hasman,et al.  Polarization dependent focusing lens by use of quantized Pancharatnam–Berry phase diffractive optics , 2003 .

[7]  J. Courtial.  Wave plates and the Pancharatnam phase , 1999 .

[8]  Qiaofeng Tan,et al.  Three-dimensional optical holography using a plasmonic metasurface , 2013, Nature Communications.

[9]  Federico Capasso,et al.  Ultra-thin plasmonic optical vortex plate based on phase discontinuities , 2012 .

[10]  Federico Capasso,et al.  Out-of-plane reflection and refraction of light by anisotropic optical antenna metasurfaces with phase discontinuities. , 2012, Nano letters.

[11]  Shuangchun Wen,et al.  Identifying graphene layers via spin Hall effect of light , 2012, 1208.1168.

[12]  R. Boyd,et al.  Optical spin-to-orbital angular momentum conversion in ultra-thin metasurfaces with arbitrary topological charges , 2014, 1407.5491.

[13]  S. Wen,et al.  Experimental observation of the spin Hall effect of light on a nanometal film via weak measurements , 2011, 1112.4560.

[14]  Hong Yang,et al.  Observation of the in-plane spin separation of light. , 2011, Optics express.

[15]  Enhancing or suppressing the spin Hall effect of light in layered nanostructures , 2011, 1105.2936.

[16]  Shuangchun Wen,et al.  Enhanced and switchable spin Hall effect of light near the Brewster angle on reflection , 2011, 1108.2605.

[17]  Onur Hosten,et al.  Observation of the Spin Hall Effect of Light via Weak Measurements , 2008, Science.

[18]  K. Bliokh,et al.  Geometrodynamics of spinning light , 2008, 0810.2136.

[19]  A. Alú,et al.  Twisted optical metamaterials for planarized ultrathin broadband circular polarizers , 2012, Nature Communications.

[20]  Erez Hasman,et al.  Optical spin Hall effects in plasmonic chains. , 2011, Nano letters.

[21]  N. Yu,et al.  Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction , 2011, Science.

[22]  Erez Hasman,et al.  Polarization beam-splitters and optical switches based on space-variant computer-generated subwavelength quasi-periodic structures , 2002 .

[23]  Vladimir M. Shalaev,et al.  Ultra-thin, planar, Babinet-inverted plasmonic metalenses , 2013, Light: Science & Applications.

[24]  Erez Hasman,et al.  Coriolis effect in optics: unified geometric phase and spin-Hall effect. , 2008, Physical review letters.

[25]  Shuangchun Wen,et al.  Realization of Tunable Photonic Spin Hall Effect by Tailoring the Pancharatnam-Berry Phase , 2013, Scientific Reports.

[26]  Qiaofeng Tan,et al.  Helicity dependent directional surface plasmon polariton excitation using a metasurface with interfacial phase discontinuity , 2013, Light: Science & Applications.

[27]  N. Yu,et al.  Flat optics with designer metasurfaces. , 2014, Nature materials.

[28]  Yan Li,et al.  Impact of in-plane spread of wave vectors on spin Hall effect of light around Brewster's angle , 2013 .

[29]  S. Bozhevolnyi,et al.  Broadband focusing flat mirrors based on plasmonic gradient metasurfaces. , 2013, Nano letters.

[30]  Ebrahim Karimi,et al.  Generating optical orbital angular momentum at visible wavelengths using a plasmonic metasurface , 2014, Light: Science & Applications.

[31]  Qihuang Gong,et al.  Measurement of spin Hall effect of reflected light. , 2009, Optics Letters.

[32]  Shuangchun Wen,et al.  Realization of polarization evolution on higher-order Poincaré sphere with metasurface , 2014, 1407.1997.

[33]  Erez Hasman,et al.  Dielectric gradient metasurface optical elements , 2014, Science.

[34]  Erez Hasman,et al.  Formation of helical beams by use of Pancharatnam-Berry phase optical elements. , 2002, Optics letters.

[35]  E. Hasman,et al.  Spin-Optical Metamaterial Route to Spin-Controlled Photonics , 2013, Science.

[36]  Shuichi Murakami,et al.  Hall effect of light. , 2004, Physical review letters.

[37]  L. Marrucci,et al.  Optical spin-to-orbital angular momentum conversion in inhomogeneous anisotropic media. , 2006, Physical review letters.

[38]  Y. Wang,et al.  Photonic Spin Hall Effect at Metasurfaces , 2013, Science.

[39]  Edwin Yue-Bun Pun,et al.  Spin-enabled plasmonic metasurfaces for manipulating orbital angular momentum of light. , 2013, Nano letters.

[40]  Andrea Alù,et al.  Manipulating light polarization with ultrathin plasmonic metasurfaces , 2011 .

[41]  A. Kildishev,et al.  Planar Photonics with Metasurfaces , 2013, Science.

[42]  Vladimir M. Shalaev,et al.  Metasurface holograms for visible light , 2013, Nature Communications.

[43]  P. Kazansky,et al.  Polarization sensitive elements fabricated by femtosecond laser nanostructuring of glass [Invited] , 2011 .