Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Unidirectional reflectionless anti-parity-time-symmetric photonic lattices of thermal atoms

Yanyan He, Jinze Wu, Yaodong Hu, Junxiang Zhang, Shi‐Yao Zhu

Published Apr 18, 2022• 26 citations
Publisher

Abstract

We experimentally demonstrate an anti-parity-time (anti-$PT$)-symmetric photonic lattice in thermal cesium atoms driven by two standing-wave laser fields. Such a lattice possesses anti-$PT$-symmetric susceptibility, of which the real (imaginary) part is an odd (even) function of position. By manipulating the intensities and phases of the two standing-wave fields, we experimentally observe unidirectional reflectionless propagation at the exceptional points. Our work provides a platform to study the scattering property of anti-$PT$-symmetric systems.

DOI
10.1103/physreva.105.043712

Related papers

Parity-time-antisymmetric atomic lattices without gain

Jin‐Hui Wu, M. Artoni, Giuseppe Carlo La Rocca

Lossy atomic photonic crystals can be suitably tailored so that the real and imaginary parts of the susceptibility are, respectively, an odd and an even function of position. Such a parity-time $(PT)$ space antisymmetry in the susceptibility requires neither optical gain nor negative refraction, but is rather attained by a combined control of the spatial modulation of both the atomic density and their dynamic level shift. These passive photonic crystals made of dressed atoms are characterized by a tunable unidirectional reflectionlessness accompanied by an appreciable degree of transmission. Interestingly, such peculiar properties are associated with non-Hermitian degeneracies of the crystal scattering matrix, which can then be directly observed through reflectivity measurements via a straightforward phase modulation of the atomic dynamic level shift and even off resonance.

Physical Review A•Mar 11, 2015•77 citations

Asymmetric diffraction in anti-parity-time symmetry of non-Hermitian photonic lattice

Runrun Li, Hengfei Zhang, Jinpeng Yuan +3 more

Non-Hermitian systems based on anti-parity-time (PT) symmetry reveal rich physics beyond the Hermitian regime. Here, the anti-PT-symmetric photonic lattice is effectively achieved in a four-level inverted Y-type 85 Rb atomic vapor. Such instantaneously reconfigurable anti-PT-symmetric photonic lattice possessing susceptibility of 𝜒 ⁡ ( 𝑥 ) = − 𝜒 ∗ ⁡ ( − 𝑥 ) , is established by a one-dimensional standing-wave coupling field under the assist of a standing-wave driving field. The input probe beam experiences a periodic refractive index modulation when traveling through the photonic lattice, the evolution of output diffraction patterns with symmetric, asymmetric, and lopsided intensity distribution is obtained by adjusting the relevant parameters of constructed non-Hermitian system. Moreover, the anti-PT symmetry in two-dimensional case of both square and hexagonal lattices are correspondingly realized. Our work promotes the development of non-Hermitian devices, and also has some important applications in quantum simulation .

Results in Physics•Aug 23, 2024•1 citation

Unidirectional and bidirectional photon transport blockade in driven atomic lattices of parity-time antisymmetry

Xiao Liu, Jin‐Hui Wu

Abstract We propose a scheme for realizing exact parity-time ( P T ) antisymmetry of complex susceptibility in a wide range of probe detuning by considering a one-dimensional lattice of cold atoms driven into the simplest three-level Λ configuration. This is attained by modulating the intensity of a standing-wave coupling field with a proper phase shift to counteract the product of a single-photon detuning and a two-photon detuning. Such a dynamically controlled P T -antisymmetric lattice supports the integration of a few nontrivial scattering behaviors including unidirectional light reflectionless, asymmetric perfect absorption, and directional signal quenching. These behaviors, depending in particular on atomic densities and lattice lengths, facilitate the on-demand realization of unidirectional or bidirectional photon transport blockade.

New Journal of Physics•Jan 1, 2024•6 citations

Experimental observation of partial parity-time symmetry and its phase transition with a laser-driven cesium atomic gas

Yongmei Xue, Chao Hang, Yunhui He +5 more

Realizing and manipulating parity-time ($\mathcal{PT}$) symmetry in multidimensional systems are highly desirable for the exploration of nontrivial physics and the discovery of exotic phenomena in non-Hermitian systems. Finding non-Hermitian systems that still have all-real spectra even if their Hamiltonians possess only partial $\mathcal{PT}$ symmetry has also attracted tremendous attention in recent years. Here, we report the experimental observation of partial $\mathcal{PT}$ symmetry in a cesium atomic gas coupled with laser fields, where a two-dimensional partially $\mathcal{PT}$-symmetric optical potential for a probe laser beam is created. A transition of the partial $\mathcal{PT}$ symmetry from an unbroken phase to a broken one is observed through changing the beam-waist ratio of the control and probe laser beams, and the domains of unbroken, broken, and nonpartial $\mathcal{PT}$ phases are also discriminated unambiguously. Moreover, we develop a technique to precisely determine the exceptional point location of the partial $\mathcal{PT}$ symmetry breaking by measuring the asymmetry degree of the probe-beam intensity distribution. The findings reported here pave the way for controlling multidimensional laser beams in non-Hermitian systems via laser-induced atomic coherence, and have potential applications for designing light amplifiers and attenuators in different parts of laser beams.

arXiv:2109.09275•Physical Review A•May 17, 2022•16 citations

Optical 𝒫𝒯-symmetry and 𝒫𝒯-antisymmetry in coherently driven atomic lattices

Xin Wang, Jin-Hui Wu

We study an ensemble of ultracold atoms trapped in the one-dimensional optical lattices under the N level configuration to examine the absorption and dispersion properties modulated into different ways along the lattice direction z. We find these trapped atoms with a Gaussian density distribution in each period may exhibit either symmetry χp(z)=χp*(-z) or antisymmetry χp(z)=-χp*(-z) of parity-time (PT) in terms of the probe susceptibility. Such intriguing twofold modulations of real (χ'p) and imaginary (χ″p) susceptibilities with a π/2 phase shift are attained by spatially modulating intensities or frequencies of one driving field in a suitable way. The PT-symmetric or PT-antisymmetric atomic lattices correspond in fact to complex photonic crystals and may be extended to develop functional devices like photonic diodes and transistors, a task impossible for real photonic crystals.

Optics Express•Feb 19, 2016•60 citations

Discrete dynamics of light in an anti-parity-time symmetric photonic lattice in atomic vapors

Qingsong Yu, Jiaqi Yuan, Zhenzhi Liu +4 more

Rb atomic system both experimentally and theoretically. Such an instantaneously reconfigurable anti-PT-symmetric photonic lattice is "written" by two one-dimensional coupling fields, which are arranged alternately along the x direction and can modulate the refractive index of the atomic vapor in a spatially periodical manner via controllable atomic coherence. By properly adjusting the relevant atomic parameters, the phase shift between two adjacent lattice channels occurs in the constructed non-Hermitian photonic system. Such a readily reconfigurable anti-PT-symmetric photonic lattice may open the door for demonstrating the discrete characteristics of the optical waves in periodic anti-PT-symmetric photonic systems.

Optics Letters•Oct 9, 2023•8 citations
We experimentally demonstrate an anti-parity-time (anti-PTPTPT)-symmetric photonic lattice in thermal cesium atoms driven by two standing-wave laser fields. Such a lattice possesses anti-PTPTPT-symmetric susceptibility, of which the real (imaginary) part is an odd (even) function of position. By manipulating the intensities and phases of the two standing-wave fields, we experimentally observe unidirectional reflectionless propagation at the exceptional points. Our work provides a platform to study the scattering property of anti-PTPTPT-symmetric systems.
Lossy atomic photonic crystals can be suitably tailored so that the real and imaginary parts of the susceptibility are, respectively, an odd and an even function of position. Such a parity-time (PT)(PT)(PT) space antisymmetry in the susceptibility requires neither optical gain nor negative refraction, but is rather attained by a combined control of the spatial modulation of both the atomic density and their dynamic level shift. These passive photonic crystals made of dressed atoms are characterized by a tunable unidirectional reflectionlessness accompanied by an appreciable degree of transmission. Interestingly, such peculiar properties are associated with non-Hermitian degeneracies of the crystal scattering matrix, which can then be directly observed through reflectivity measurements via a straightforward phase modulation of the atomic dynamic level shift and even off resonance.
Non-Hermitian systems based on anti-parity-time (PT) symmetry reveal rich physics beyond the Hermitian regime. Here, the anti-PT-symmetric photonic lattice is effectively achieved in a four-level inverted Y-type 85 Rb atomic vapor. Such instantaneously reconfigurable anti-PT-symmetric photonic lattice possessing susceptibility of 𝜒 ⁡ ( 𝑥 ) = − 𝜒 ∗ ⁡ ( − 𝑥 ) , is established by a one-dimensional standing-wave coupling field under the assist of a standing-wave driving field. The input probe beam experiences a periodic refractive index modulation when traveling through the photonic lattice, the evolution of output diffraction patterns with symmetric, asymmetric, and lopsided intensity distribution is obtained by adjusting the relevant parameters of constructed non-Hermitian system. Moreover, the anti-PT symmetry in two-dimensional case of both square and hexagonal lattices are correspondingly realized. Our work promotes the development of non-Hermitian devices, and also has some important applications in quantum simulation .
Abstract We propose a scheme for realizing exact parity-time ( P T ) antisymmetry of complex susceptibility in a wide range of probe detuning by considering a one-dimensional lattice of cold atoms driven into the simplest three-level Λ configuration. This is attained by modulating the intensity of a standing-wave coupling field with a proper phase shift to counteract the product of a single-photon detuning and a two-photon detuning. Such a dynamically controlled P T -antisymmetric lattice supports the integration of a few nontrivial scattering behaviors including unidirectional light reflectionless, asymmetric perfect absorption, and directional signal quenching. These behaviors, depending in particular on atomic densities and lattice lengths, facilitate the on-demand realization of unidirectional or bidirectional photon transport blockade.
Realizing and manipulating parity-time (PT\mathcal{PT}PT) symmetry in multidimensional systems are highly desirable for the exploration of nontrivial physics and the discovery of exotic phenomena in non-Hermitian systems. Finding non-Hermitian systems that still have all-real spectra even if their Hamiltonians possess only partial PT\mathcal{PT}PT symmetry has also attracted tremendous attention in recent years. Here, we report the experimental observation of partial PT\mathcal{PT}PT symmetry in a cesium atomic gas coupled with laser fields, where a two-dimensional partially PT\mathcal{PT}PT-symmetric optical potential for a probe laser beam is created. A transition of the partial PT\mathcal{PT}PT symmetry from an unbroken phase to a broken one is observed through changing the beam-waist ratio of the control and probe laser beams, and the domains of unbroken, broken, and nonpartial PT\mathcal{PT}PT phases are also discriminated unambiguously. Moreover, we develop a technique to precisely determine the exceptional point location of the partial PT\mathcal{PT}PT symmetry breaking by measuring the asymmetry degree of the probe-beam intensity distribution. The findings reported here pave the way for controlling multidimensional laser beams in non-Hermitian systems via laser-induced atomic coherence, and have potential applications for designing light amplifiers and attenuators in different parts of laser beams.
We study an ensemble of ultracold atoms trapped in the one-dimensional optical lattices under the N level configuration to examine the absorption and dispersion properties modulated into different ways along the lattice direction z. We find these trapped atoms with a Gaussian density distribution in each period may exhibit either symmetry χp(z)=χp*(-z) or antisymmetry χp(z)=-χp*(-z) of parity-time (PT) in terms of the probe susceptibility. Such intriguing twofold modulations of real (χ'p) and imaginary (χ″p) susceptibilities with a π/2 phase shift are attained by spatially modulating intensities or frequencies of one driving field in a suitable way. The PT-symmetric or PT-antisymmetric atomic lattices correspond in fact to complex photonic crystals and may be extended to develop functional devices like photonic diodes and transistors, a task impossible for real photonic crystals.
Rb atomic system both experimentally and theoretically. Such an instantaneously reconfigurable anti-PT-symmetric photonic lattice is "written" by two one-dimensional coupling fields, which are arranged alternately along the x direction and can modulate the refractive index of the atomic vapor in a spatially periodical manner via controllable atomic coherence. By properly adjusting the relevant atomic parameters, the phase shift between two adjacent lattice channels occurs in the constructed non-Hermitian photonic system. Such a readily reconfigurable anti-PT-symmetric photonic lattice may open the door for demonstrating the discrete characteristics of the optical waves in periodic anti-PT-symmetric photonic systems.