Constructions of synthetic lattices in photonics attract growingly attentions for exploring interesting physics beyond the geometric dimensionality, among which modulated ring resonator system has been proved as a powerful platform to create different kinds of connectivities between resonant modes along the synthetic frequency dimension with many theoretical proposals. Various experimental realizations are investigated in a single ring resonator, while building beyond simple synthetic lattices in multiple rings with different types remains lacking, which desires to be accomplished as an important step further. Here, we implement the experimental demonstration of generating the one-dimensional Lieb lattice along the frequency axis of light, realized in two coupled ring resonators while the larger ring undergoing dynamic modulation. Such synthetic photonic structure naturally exhibits the physics of flat band. We show that the time-resolved band structure read out from the drop-port output of the excited ring is the intensity projection of the band structure onto specific resonant mode in the synthetic momentum space, where gapless flat band, mode localization effect, and flat to non-flat band transition are observed in experiments and verified by simulations. Our work gives a direct evidence for the constructing synthetic Lieb lattice with two rings, which hence makes a solid step towards experimentally constructing more complicated lattices in multiple rings associated with synthetic frequency dimension.

Last. Shanhui Fan(Stanford University)H-Index: 143

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The concept of synthetic dimensions in photonics has attracted rapidly growing interest in the past few years. Among a variety of photonic systems, the ring resonator system under dynamic modulation has been investigated in depth both in theory and experiment and has proven to be a powerful way to build synthetic frequency dimensions. In this Tutorial, we start with a pedagogical introduction to the theoretical approaches in describing the dynamically modulated ring resonator system and then rev...

Last. Shanhui Fan(Stanford University)H-Index: 143

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The synthetic dimension, a research topic of both fundamental significance and practical applications, has been attracting increasing attention in recent years. In this paper, we propose a theoretical framework to construct arbitrary synthetic dimensions, or N-boson synthetic lattices, using multiple bosons on one-dimensional lattices. We show that a one-dimensional lattice hosting N indistinguishable bosons can be mapped to a single boson on an N-dimensional lattice with high symmetry. Band str...

Topological photonics is a new and rapidly growing field that deals with topological phases and topological insulators for light. Recently, the scope of these systems was expanded dramatically by incorporating non-spatial degrees of freedom. These synthetic dimensions can range from a discrete ladder of cavity modes or Bloch modes of an array of waveguides to a time-bin division (discrete time steps) in a pulsed system or even to parameters such as lattice constants. Combining spatial and synthe...

In the last few decades, topological phase1–11 has emerged as a new classification of matter states beyond the Ginzburg–Landau symmetry-breaking paradigm. The underlying global invariant is usually well characterized by integers, such as Chern numbers or winding numbers—the Abelian charges12–15. Very recently, researchers proposed the notion of non-Abelian topological charges16–19, which possess non-commutative and fruitful braiding structures with multiple (more than one) bandgaps tangled toget...

Synthetic dimensions, which simulate spatial coordinates using non-spatial degrees of freedom, are drawing interest in topological science and other fields for modelling higher-dimensional phenomena on simple structures. We present the first realization of a synthetic frequency dimension on a silicon ring resonator photonic device fabricated using a CMOS process. We confirm that its coupled modes correspond to a 1D tight-binding model through acquisition of up to 280 GHz bandwidth optical freque...

Optical frequency division via optical frequency combs has enabled a leap in microwave metrology, leading to noise performance never explored before. Extending this method to the millimetre-wave and terahertz-wave domains is of great interest. Dissipative Kerr solitons in integrated photonic chips offer the unique feature of delivering optical frequency combs with ultrahigh repetition rates from 10 GHz to 1 THz, making them relevant gears for performing optical frequency division in the millimet...

Last. Shanhui Fan(Stanford University)H-Index: 143

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The nontrivial topological features in the energy band of non-Hermitian systems provide promising pathways to achieve robust physical behaviors in classical or quantum open systems. A key topological feature of non-Hermitian systems is the nontrivial winding of the energy band in the complex energy plane. We provide experimental demonstrations of such nontrivial winding by implementing non-Hermitian lattice Hamiltonians along a frequency synthetic dimension formed in a ring resonator undergoing ...

#1Hao Chen(HUST: Huazhong University of Science and Technology)H-Index: 6

#2Ningning Yang(HUST: Huazhong University of Science and Technology)H-Index: 2

Last. Peixiang Lu(HUST: Huazhong University of Science and Technology)H-Index: 59

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Bloch oscillations (BOs) were initially predicted for electrons in a solid lattice to which a static electric field is applied. The observation of BOs in solids remains challenging due to the collision scattering and barrier tunnelling of electrons. Nevertheless, analogies of electron BOs for photons, acoustic phonons and cold atoms have been experimentally demonstrated in various lattice systems. Recently, BOs in the frequency dimension have been proposed and studied by using an optical micro-r...

Last. Xianfeng Chen(SDNU: Shandong Normal University)H-Index: 30

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Band structure theory plays an essential role in exploring physics in both solid-state systems and photonics. Here, we demonstrate a direct experimental measurement of the dynamic band structure in a synthetic space including the frequency axis of light, realized in a ring resonator under near-resonant dynamic modulation. This synthetic lattice exhibits the physical picture of the evolution of the wave vector reciprocal to the frequency axis in the band structure, analogous to a one-dimensional ...

Non-Hermitian skin effect (NHSE) has led to interesting physics and sophisticated applications beyond the conventional framework. However, NHSE studies have been limited to an individual dimension due to the difficulty of constructing nonreciprocal coupling in higher-dimensional systems. With the concept of synthetic dimension, we realize two-dimensional (2D) NHSE in a synthetic photonic lattice. The synthetic photonic lattice is composed of a spatial dimension and a synthetic frequency dimensio...