High-resolution spectroscopy unveils the fundamental physics of quantum states, molecular dynamics, and energy transfers. Ideally, a higher spectral resolution over a broader bandwidth is the prerequisite, but traditional spectroscopic techniques can only partially fulfill this requirement even with a bulky system. Here we report that a multi-frequency acousto-optic phase modulation at a chip-scale of soft polydimethylsiloxane can readily support a 200-times higher 0.5-MHz spectral resolution for the frequency-comb-based spectroscopy, while co-located plasmonic nanostructures mediate the strong light-matter interaction. These results suggest the potential of polydimethylsiloxane acousto-optic phase modulation for cost-effective, compact, multifunctional chip-scale tools in diverse applications such as quantum spectroscopy, high-finesse cavity analysis, and surface plasmonic spectroscopy.

- Authors (Pusan National University): San Kim (Department of Cogno-Mechatronic Engineering), Seungchul Kim (Department of Optics & Mechatronics Engineering) 

- Title of original paper: Interleaved frequency comb by chip-scale acousto-optic phase modulation at polydimethylsiloxane for higher-resolution direct plasmonic comb spectroscopy

- Journal: PhotoniX

- Web link: https://doi.org/10.1186/s43074-025-00170-x 

- Contact e-mail: s.kim@pusan.ac.kr