Chip-Scale Wave-Matter Interactions at RF to Light Frequencies: CMOS Spectroscopic Systems for Molecular Sensing, Time-Keeping and Magnetometry
Rm 5506, 5/F (Lift 25, 26), Academic Building, HKUST


Silicon integrated circuits have led to significant cost and size reduction of RF/millimetere-wave sensing systems, such as radars and imagers. Essentially, almost all of those sensors are based on wave absorption/scattering at macroscopic-scale objects that are insensitive to wave frequencies. While this catogery will continue thriving, new frontiers of electromagnetic (EM) spectral sensors are emerging. Nowadays, silicon circuits are quickly filling up the THz gap with, for example, radiation at 1THz approaching mW level. Meanwhile, their nano-scale on-chip patterns have enabled implementation of photonic structures. In this talk, I show that such extension of spectral coverage is enabling new sensing microsystems and applications utilizing interactions between microscopic particles (molecules, atoms, electrons…) and RF-to-light waves.

To showcase the above trend, I will present a few CMOS spectroscopic systems for quantum-state excitation/detection at the chip scale via high-precision, frequency-controlled waves. Probing the rotational mode of molecules at 220~320GHz, the first system based on a dual-frequency-comb architecture offers rapid, seamless spectral sensing and molecular detection in gas with absolute specificity. Next, by locking to a sub-THz transition of carbonyl sulfide (OCS) gas molecules confined in a THz waveguide, a miniature molecular clock is demonstrated with frequency stability comparable to that of chip-scale atomic clocks but much lower complexity and cost. Lastly, we present a room-temperature, quantum magnetometer using CMOS-compatible photonic components and microwave launcher with high field uniformity. It probes the Zeeman splitting of nitrogen-vacancy (NV) centers in chip-attached diamond and delivers excellent vector-field sensitivity. This new catogery of silicon EM-spectral sensors are expected to greatly advance the capabilities and accessibility of chemical analysis, bio-medical diagnosis/research, navigation, networking and security.



Professor Ruonan Han received his Ph.D. degree in electrical and computer engineering from Cornell University in 2014. Prior to that, he received his B.Sc. degree in microelectronics from Fudan University in 2007 and M.Sc. degree in electrical engineering from the University of Florida in 2009. He is currently an associate professor with the Department of Electrical Engineering and Computer Science at Massachusetts Institute of Technology. 

The research of Prof. Han has focused on millimeter-wave and terahertz integrated circuits and microsystems for emerging sensing and communication technologies. He was the recipient of the IEEE Solid-State Circuits Society (SSCS) Pre-Doctoral Achievement Award, the IEEE Microwave Theory and Tech. Society (MTT-S) Graduate Fellowship Award, the Best Student Paper Award of two IEEE RFIC symposia (2012 and 2017), and the Director’s Best Thesis Award at Cornell University. He is the associate editor of IEEE Transactions on Very-Large-Scale-Integration (VLSI) Systems, and also serves on the technical program committee of IEEE RFIC symposium and Intl. Microwave Symposium (IMS), as well as the steering committee of IMS. He held the MIT E. E. Landsman (1958) Career Development Chair Professorship in 2014~2017, and is the winner of the National Science Foundation (NSF) CAREER Award in 2017.


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Rm 5506, 5/F (Lift 25, 26), Academic Building, HKUST