Scalable On-Chip Photonic Simulator for Complex Frequency Lattices

Researchers from the University of Science and Technology of China, led by Professor Chuanfeng Li, have made notable advancements in quantum photonics. They developed an on-chip photonic simulator to model arbitrary-range coupled frequency lattices with gauge potential. The findings were published in Physical Review Letters.

A key goal in quantum physics has been to design efficient simulators that can accurately replicate the dynamics of complex systems. Photonic systems, with their ability to control properties such as frequency and polarization, have emerged as promising candidates for quantum simulations.

A major challenge in this area is constructing frequency lattices capable of simulating intricate structures like atomic chains and nanotubes, which are critical for studying low-dimensional materials.

To address this, the team used thin-film lithium niobate chips, known for their high electro-optic coefficient, to create frequency-domain lattices. They achieved a breakthrough by observing band structures through periodic modulation of an on-chip resonator, enabling simulations of structures with arbitrary-range coupling. This approach reduced the required modulation frequency by over five orders of magnitude while achieving coupling up to eight or nine times the lattice constant.

This was accomplished by combining multiple lattice points into a single resonant peak, simplifying the application and detection of multi-harmonic signals on ultrahigh-frequency chips.

The research emphasizes low-frequency radio-frequency modulation, offering significant flexibility in defining lattice points and controlling compound interactions. Their method reduced modulation frequencies from nearly 100 GHz to about 10 MHz, a decrease of over three orders of magnitude. This innovation lowers the demands on source and measurement equipment while simplifying design and fabrication processes.

The study also addresses the challenges posed by high frequencies in on-chip synthetic dimensions while maintaining scalability for extending conventional methods to higher-dimensional models. It demonstrates the potential for creating high-dimensional and complex frequency synthetic dimensions using thin-film lithium niobate optical chips.

Reviewers of the study praised it as a major contribution to the field, noting that it "opens a new avenue for exploring synthetic dimensions on photonic chips."

Journal Reference:

‌Wang, Z.-A., et al. (2024) On-Chip Photonic Simulating Band Structures towards Arbitrary-Range Coupled Frequency Lattices. Physical Review Letters. doi.org/10.1103/physrevlett.133.233805.