Recently, the Center, in collaboration with the School of Physics, Peking University, the Center for Frontier Science in Nano-Optoelectronics, the State Key Laboratory of Artificial Microstructures and Mesoscopic Physics led by Prof. Xiao Yunfeng and Academician Gong Qihuang, has made significant progress in the research of micro-nano optical sensing. A new approach to sensing using a combination of optical dark-field aberration interferometry and frequency conversion has reduced the real-time signal sampling noise by two orders of magnitude and successfully achieved highly sensitive detection of polystyrene nanoparticles and individual virus-like particles.
Optical swift field sensors have unique advantages such as ultra-high sensitivity and non-labeling, and play an important role in precision measurement, environmental safety, life and health, and other applications. However, the low-frequency electrical noise inherent in the sensing process, which consists mainly of 1 / f low-frequency noise, makes dynamic monitoring of many important biochemical processes (e.g., antigen-antibody reactions, cell motility, and DNA hybridization) difficult to achieve.
Therefore, the joint group proposes a new method of sensing through optical dark-field aberration interferometry combined with frequency conversion, which can efficiently suppress 1/f noise (Fig. 1a) and realizes ultra-high sensitivity detection of nanoscale single particles through CMOS-compatible dark-field aberration waveguide interferometric structures (Fig. 1b). In the experiment, the sampling noise amplitude was suppressed by two orders of magnitude, enabling the successful detection of individual polystyrene particles with a radius of 30 nm (signal-to-noise ratio of more than 14 dB) and human immunodeficiency virus type 1 (HIV-1)-like particles (SNR ∼20 dB). Through the statistics and analysis of the sensing signals, the detection limit is expected to be further increased and precise measurement of nanoparticle size will be achieved. In addition, the joint group also proposed an integrated waveguide array scheme, which significantly improves the detection speed and is expected to realize the composite detection of multiple viruses or molecules.
Fig. 1 (a) 1/f noise suppression mechanism; (b) single-particle detection based on on-chip waveguide dark-field heterodyne interferometry
On March 30, 2021, the research results were published online in Nature Communications under the title "1/f-noise-free optical sensing with an integrated heterodyne interferometer". The first authors are Ming Jin, a PhD student of 2017, and Crystal Tang, a Burson-Marsteller postdoctoral fellow from the School of Physics, and corresponding authors are Prof. Xingjun Wang and Prof. Yunfeng Xiao. Researcher Kuangshi Chen of the College of Engineering provided HIV-1 virus-like particles, which strongly supported this study.
The above work was supported by the National Natural Science Foundation of China, the National Key Research and Development Program of China, the State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, the State Key Laboratory of Regional Optical Fiber Communication Networks and Novel Optical Communication Systems, and the High Performance Computing Platform of Peking University.
Link to the original paper:
https://www.nature.com/articles/s41467-021-22271-4
