Schematic of the experimental platform of a photonic resonator under dynamical modulation. Credit: Shanhui Fan
A team of researchers at Stanford University has developed a novel spectroscopy technique to analyze multi-dimensional band structure in the photonic synthetic frequency dimension. The new technique will increase understanding of high-dimensional systems, and drive innovations in a number of industries.
Currently, measurements in the photonic synthetic frequency dimension are limited to one-dimensional Brillouin zones or single-dimensional subsets of three-dimensional Brillouin zones. With the new technique developed researchers are able to conduct measurements across the entire multidimensional Brillouin zone, providing a more comprehensive understanding of the physics and behavior of high-dimensional regimes.
In the study, published in Light Science & Applications, the entire lattice band structure of a multi-dimensional Brillouin zone was resolved using a single photonic resonator. To create a multi-dimensional lattice in the synthetic frequency dimension, the researchers used multiple modulation frequencies. To measure this band structure a tunable frequency laser was used to excite the resonator and time-dependant transmission signals were collected using a photodetector. By sweeping the frequency of the input laser, band energies were able to be extracted from the transmission spectrum.
“The essence of the synthetic dimension lies in the potential to expand our toolbox in high-dimensional physics. Considering the wealth of physical information embedded in the band structures, we believe that the multi-dimensional band structure spectroscopy represents a crucial milestone in this direction. It will facilitate our comprehension and manipulation of high-dimensional systems, and potentially provide inspirations for optical devices with innovative functionalities,” the researchers commented.
The methodologies presented in this research bring us closer than ever before to understanding and harnessing the capabilities of non-Hermitian systems. The findings are sure to bring advancements to the fields of physics and engineering.