Design of metasurface polarizers based on two-dimensional cold atomic arrays

Abstract

Engineering light-matter interaction using cold atomic arrays is one of the central topics in modern optics. Here we have demonstrated the capability of two-dimensional asymmetric cold atomic arrays as microscopic metasurfaces for controlling polarization states of light. The designed linear polarizer can lead to an extinction ratio over 20dB as well as a high transmittance over 0.8 for the permitted polarization at zero detuning. For detuned driving light, changing lattice constants can also achieve high performance linear polarizers. We have also accomplished a circular polarizer by manipulating the phases of transmitted light. A theoretical analysis based on Bloch theorem shows the underlying mechanism for this performance is actually attributed to cooperative effects in periodic lattices. Finally, we discuss in detail the effects of system size, lattice imperfection and nonzero driving light linewidth in practical implementation. The present study paves a way to design extremely miniaturized metasurfaces using cold atoms and other two-level systems, showing great potential in quantum information and quantum metrology sciences as well as the fundamental physics of light-matter interaction.

Mitigating Chromatic Dispersion with Hybrid Optical Metasurfaces

“…Low‐efficiency achromatic broadband response has even been reported by manipulating scalar properties of light or by utilizing structural dispersion of surface plasmon polaritons in metal–insulator–metal waveguides to compensate for metal dispersion . Various high‐efficient components like polarizers, holograms, beam splitters have been already designed using metasurfaces. A recent report on gradient silicon metasurface device showed a beam deflector having 71% transmission efficiency and 95% diffraction efficiency, and operating at a specific wavelength of 532 nm .…”

Near-resonant light transmission in two-dimensional dense cold atomic media with short-range positional correlations

“…where p j (ω) is the excited dipole moment of j-th atom, E inc is the electric field of the incident light. Here α(ω) is the polarizability of the two-level atom, which under our assumptions is described as [74,104,105]…”

Topological quantum optical states in quasiperiodic cold atomic chains

“…By applying the single excitation approximation (which is valid for sufficiently weakly excited system) [45][46][47], we can work in the subspace spanned by the ground states |G ≡ |g...g and the single excited states |i ≡ |g...e i ...g of the atoms [45][46][47]. Moreover, by adiabatically eliminating the photonic degrees of freedom in the reservoir (i.e., the quantized electromagnetic field), we obtain the effective Hamiltonian describing light-atom interaction in the absence of any external driving field as [16,17,21,23,[45][46][47][48][49]…”

“…Owing to the irrational nature of the interatomic distance modulation, the band structures thus break into a set of fractal bands and gaps (more precisely, for an infinitely long chain, the spetrum constitutes a Cantor set [54]), with several main gaps clearly visible, while many minigaps in the spectra can only be seen in an enlarged figure. With the increase of the modulation amplitude η, the main gaps become wider because the near-field dipole-dipole interactions between atoms can give rise to very strong frequency shift thus open larger band gaps [17].…”

“…Conventional topological optical states are usually created by using dielectric and metallic materials with artificially carved micro/nanostructures [2]. On the other hand, topological optical states can also be engineered in ultracold atom settings by utilizing the state-of-art versatile control of lightatom interactions [13], especially using the cooperative quantum optical states in cold atom arrays [14][15][16][17]. Current laser cooling and trapping technologies allow the creation of almost arbitrary geometries of atom arrays in a relatively large scale [18][19][20].…”