Observation of temporal reflection and broadband frequency translation at photonic time interfaces

Moussa, Hady; Xu, Gengyu; Yin, Shixiong; Galiffi, Emanuele; Ra’di, Younes; Alù, Andrea

doi:10.1038/s41567-023-01975-y

Cited by 78 publications

(24 citation statements)

References 37 publications

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“…Note that the physical origin of the zero reflection as revealed here is fundamentally different from those in the space-or time-engineered media: the zero reflection here results from the proper phase accumulation in both space and time, while in the spatial (temporal) counterpart, the zero reflection is solely induced by the proper phase accumulation in space (time). [23] Next, we proceed to analyze the influence of the spatiotemporal quarter-wave impedance transformer on the field distributions under the plane-wave excitations. We set the thickness of the spatiotemporal quarter-wave impedance transformer by using a = 1, and 𝛽 = 0.2 for subluminal interface and 𝛽 = 1.25 for the superluminal interface, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…This is because light scattering in space-(time-) engineered media has to follow the frequency (momentum) conservation due to the preserved time-(space-) translational symmetry. [23] It is interesting to ask what the condition is to achieve the spatiotemporal version of quarter-wave impedance transformer. To address this question, we investigate the reflection coefficients of the reflected waves scattered from the moving-interface media.…”

Section: Principle and Designmentioning

confidence: 99%

“…Such novel media (such as temporal metamaterials and photonic time crystals) could overcome fundamental limitations usually presented in space-engineered media, including energy conservation [18] and Kramers-Kronig relations, [19] and thus enable anomalous effects such as time reversal [20,21] and frequency conversions. [22,23] These remarkable properties of time-engineered media can give rise to many exotic phenomena that are even counterintuitive for regular materials or structures. For example, a nonresonant laser is proposed due to the exponentially amplified emission of an emitter embedded in photonic time crystals.…”

Section: Introductionmentioning

confidence: 99%

“…[25] To further enhance the controllability of electromagnetic waves, spatiotemporal metamaterials have been proposed, which render novel phenomena beyond conventional physics bounds, such as magnet-free nonreciprocity, [26,27] Cherenkov radiation in the vacuum, [28] Fresnel drag, [29] and parametric amplification. [30] All these exciting theoretical breakthroughs in time-varying media (including time-engineered and spacetime-engineered media) are facilitating their experimental realizations in transmission lines, [23,31] water surface waves, [20,32] and metasurfaces. [20,33] The rapid progress in artificially engineered media inspires the generalization of numerous physical concepts initially proposed in space-engineered media into time-varying media.…”

Section: Introductionmentioning

confidence: 99%

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Antireflection Spatiotemporal Metamaterials

Zou

et al. 2023

Laser & Photonics Reviews

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Reflection occurs when light impinges on an interface between two distinct media. Suppression of the reflection is of paramount significance to practical applications in information transfer and conversion. While technologies such as the Brewster effect and material coatings are widely adopted to eliminate the wave reflection from purely spatial or temporal interfaces, how to eliminate the reflection from a spatiotemporal interface remains elusive. Here, a new type of spatiotemporal metamaterial that functions as a global and generalized perspective of quarter‐wave impedance transformers is presented. With the proper geometric design, the proposed spatiotemporal metamaterial can fully suppress the reflection, applicable to arbitrary modulation velocities. Importantly, the tunability of modulation velocity in the spatiotemporal metamaterial allows flexible frequency conversions in high efficiency, indicating that the spatiotemporal metamaterials are much more powerful than the purely spatial or temporal counterparts. These findings not only enhance the controllability of electromagnetic waves but also can be adapted to other classes of physical dynamics, including water surface waves, acoustic, and elastic.

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Section: Resultsmentioning

confidence: 99%

Section: Principle and Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Antireflection Spatiotemporal Metamaterials

Zou

et al. 2023

Laser & Photonics Reviews

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“…15). For instance, wave amplification inside the momentum bandgap of a modulated microwave metamaterial has recently been demonstrated 16 , while temporal reflections and broadband frequency translations have been demonstrated in a switched transmission-line metamaterial 17 .…”

mentioning

confidence: 99%

Photonic metamaterial analogue of a continuous time crystal

Liu

MacDonald

et al. 2023

Nat. Phys.

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Time crystals are an eagerly sought phase of matter with broken time-translation symmetry. Quantum time crystals with discretely broken time-translation symmetry have been demonstrated in trapped ions, atoms and spins whereas continuously broken time-translation symmetry has been observed in an atomic condensate inside an optical cavity. Here we report that a classical metamaterial nanostructure, a two-dimensional array of plasmonic metamolecules supported on flexible nanowires, can be driven to a state possessing all of the key features of a continuous time crystal: continuous coherent illumination by light resonant with the metamolecules’ plasmonic mode triggers a spontaneous phase transition to a superradiant-like state of transmissivity oscillations, resulting from many-body interactions among the metamolecules, characterized by long-range order in space and time. The phenomenon is of interest to the study of dynamic classical many-body states in the strongly correlated regime and applications in all-optical modulation, frequency conversion and timing.

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Quantum Antireflection Temporal Coatings: Quantum State Frequency Shifting and Inhibited Thermal Noise Amplification

Liberal

Vázquez‐Lozano

Pacheco‐Peña

2023

Laser & Photonics Reviews

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The quantum optical response of antireflection temporal coatings (ATCs), that is, matching temporal layers that suppress the generation of backward waves in temporal boundaries, is investigated. The results reveal that quantum ATCs are characterized for inducing a frequency shift of the quantum state, while preserving all photon statistics intact. Thus, they can find application for fast quantum frequency shifting in photonic quantum networks. The quantum theory also provides additional insight on their classical mode of operation, clarifying which quantities are preserved through the temporal boundary. Last, it is shown that quantum ATCs allow for fast temporal switching without amplification of thermal fields.

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Observation of temporal reflection and broadband frequency translation at photonic time interfaces

Cited by 78 publications

References 37 publications

Antireflection Spatiotemporal Metamaterials

Antireflection Spatiotemporal Metamaterials

Photonic metamaterial analogue of a continuous time crystal

Quantum Antireflection Temporal Coatings: Quantum State Frequency Shifting and Inhibited Thermal Noise Amplification

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