Nonlinear exceptional points in an integrated acoustic-wave oscillator for longwave infrared sensing
Abstract
Exceptional points (EP) featuring enhanced responsivity and rich dynamics have attracted extensive attentions in device developments and sensing applications. However, it remains debated whether employing EP systems is beneficial in practical sensing applications. Here, we demonstrate that a nonlinear EP in our microwave-frequency acoustic-wave oscillator improves longwave infrared (LWIR) detection under practical conditions. By phase tuning the nonlinear gain, our detector can be operated at different conditions with respect to the nonlinear EP. Compared with operation away from EP, our detector at EP shows a 33-fold improvement in responsivity and an 8.75-fold extension of 3-dB bandwidth. We observe a 6-fold enhancement in signal-to-noise ratio at an input modulation frequency of 6.2 kHz. At the incident LWIR wavelength of 9.6 um, our detector at EP exhibits a noise equivalent power (NEP) of 310 pW*Hz^-1/2 at input frequency of 10 kHz, yielding a figure of merit, product of NEP and time constant, of 9.87*10^-3 pW*Hz^-3/2, a 10-fold improvement over operation away from EP. Our integrated acoustic devices offer a versatile platform for exploring noise dynamics and developing practical sensors that exploit non-Hermitian nonlinearities.
Keywords
Cite
@article{arxiv.2604.27371,
title = {Nonlinear exceptional points in an integrated acoustic-wave oscillator for longwave infrared sensing},
author = {Linbo Shao and Zichen Xi and Zengyu Cen and Joseph G. Thomas and Dongyao Wang and Tanmay Singh and Liyan Zhu and Honghu Liu and Jun Ji and Yu Yao and Yizheng Zhu},
journal= {arXiv preprint arXiv:2604.27371},
year = {2026}
}