Photonic metamaterial analogue of a continuous time crystal

Abstract

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.

Roadmap for Optical Metasurfaces

“…Metamaterial-enabled noninvasive single-shot optical metrology with sub-Brownian resolution, that can be performed with high frame rate image sensors, opens up the exciting field of picophotonics. This includes the study of Brownian motion thermodynamics of nano-objects, including the ballistic regime; the study of Van Der Waals forces and non-Hamiltonian forces in nanomechanics; , configuration chemistry of individual molecules; protein folding; and other dynamic events in macromolecules and nanomachines, such as time crystals …”

“…This includes the study of Brownian motion thermodynamics of nano-objects, including the ballistic regime; 42 the study of Van Der Waals forces and non-Hamiltonian forces in nanomechanics; 43 , 44 configuration chemistry of individual molecules; protein folding; and other dynamic events in macromolecules and nanomachines, such as time crystals. 45 …”

New Horizons in Near-Zero Refractive Index Photonics and Hyperbolic Metamaterials

“…The possibility of temporally modulating the optical properties of matter via ultrafast optical pumping is establishing a new paradigm for enhanced wave control . While static nanophotonic platforms obey energy conservation and reciprocity, time-modulated systems can overcome these bounds, enabling new functionalities such as nonreciprocity, − frequency generation and translation, , time-diffraction, the engineering of photonic gauge fields, and synthetic frequency dimensions, as well as photonic Floquet matter, , among others. While the field has witnessed dramatic progress at low frequencies, leading to, e.g., the first observation of photonic time-reflection and temporal coherent wave control, the prospect of unlocking this new wave-control paradigm at near-visible frequencies represents a unique opportunity to broaden and deepen the impact horizon amidst the current rise of photonic technology …”

Conformal Spatiotemporal Modulation Enabled Geometric Frequency Combs

“…Optical frequency combs (OFCs), consisting of a train of uniformly spaced discrete spectral lines, have emerged as a vibrant and rapidly growing field in photonics and information science. , Driven by the advancement of nanofabrication technique, various platforms have been employed to generate OFCs, such as mode locked lasers − and microresonators. − Over the past decades, OFCs have been extensively investigated and demonstrated significant potential in optical spectroscopy, light detection and ranging (LIDAR), and optical communications . Owing to the breaking of time translational symmetry, temporal modulations provide an alternative approach to realize OFCs. , Distinct from uniform spatiotemporal modulations , and conventional periodic time crystals (PTCs), − the proposed conformal time-varying medium results in the generation of nonuniform OFCs, where the frequency spacings between adjacent spectral components can be flexibly tuned from quasi-uniform to geometrically progressive. Appropriately tuning of modulation speeds of spatiotemporal boundaries allows for the flexible manipulation of the spectral distribution, comb spacing, number of spectral lines, and the amplitude profiles of the designed OFCs. − In particular, the output signals can be drastically amplified through the cascaded excitation of geometric harmonics, a phenomenon similar to the luminal amplification. − Compared with linear frequency combs, the geometric comb enabled by the conformal temporal modulation can effectively suppress ambiguous peaks in its autocorrelation, , thereby leading to reverberation suppression and improved resolution for range estimation. , The broad tuning capabilities of the conformal time-varying media make the resultant OFCs suitable for various applications, particularly in the fields of spectroscopy and radar detections. , …”