The Song Group

The Song Group

Research

Human-machine interfaces

Emerging technologies such as augmented reality (AR) and brain–computer interfaces (BCI) are driving innovation in how humans interact with machines. We currently witness this with the rapid development of new handheld and wearable technologies. These technologies encompass a microcosm of electronic and optical devices that have to efficiently work together to perform a complex set of display, sensing, imaging, filtering, computation and illumination functions. We create novel ways of light-matter interactions and realize new optical devices and systems that can perform all the required functions on demand while being compatible with the restricted environments for these technologies.

Suggested readings

  • Nat. Nanotechnol. 16, 1224-1230 (2021).
  • Nat. Commun. 14, 5602 (2023).
  • Nat. Nanotechnol. 17, 1097-1103 (2022).
Resonant metasurface flat optics for human-machine interfaces. a, Eye tracking prototype system for augmented reality. b, Off-axis metasurface for folded flat optics. c, Optofluidics dynamic metasurface for electronic-paper display.
Resonant metasurface flat optics for human-machine interfaces. a, Eye tracking prototype system for augmented reality. b, Off-axis metasurface for folded flat optics. c, Optofluidics dynamic metasurface for electronic-paper display.

Quantum technologies

Quantum science is the framework of understanding physical phenomena in a perspective of wave-particle duality, clarifying a myriad of physics and chemical reactions at the fundamental level. Optical photons, bosonic quanta of electromagnetic waves at optical frequency can enable facile control over atomic transitions, chemical reactions, and any other phenomena associated with the charge oscillations. By maneuvering resonant light-matter interactions at atomic scale, we aim to manipulate emerging properties of quantum materials, atoms, and even photons at the fundamental, quantum level and create novel quantum technologies.

Suggested readings

  • Nat. Photonics 14, 426-430 (2020).
  • Nano Lett. 24, 6240-6246 (2024).
  • Nat. Commun. 6, 305-701 (2015).
Investigating and manipulating quantum properties of emerging materials and photons. a, Investigation of exciton quantum resonance of two-dimensional semiconductors. b, Enhancing quantum efficiency of photon emission.
Investigating and manipulating quantum properties of emerging materials and photons. a, Investigation of exciton quantum resonance of two-dimensional semiconductors. b, Enhancing quantum efficiency of photon emission.

Sustainable communication & computation

In step with a rapid progress of computation, communication, and their increasing needs, the requirement for carbon-free energy production and sustainable energy consumption has been becoming an emergency in a serious manner. For example, it is noted that by the end of the decade, AI data centers could consume as much as 20% to 25% of U.S. power requirements. We aim to develop ultralow-power, high-speed active optical devices and systems for communication and computation by leveraging our expertise in manipulating the light-matter interactions at the atomic scale.

Suggested readings

  • Nat. Photonics 17, 897-903 (2023).
  • Nat. Commun. 12, 1-7 (2021).
  • Nat. Commun. 13, 7848 (2022).
  • ACS Photonics 8, 872-878 (2021).
Sustainable active light modulation with atomically thin nanophotonic devices and computation imaging. a, Nanoelectromechanical system (NEMS) plasmonic dimer light modulator with sub-nanometer gap. b, Solid-state free-space light modulator with two-dimensional semiconductor. c, Metasurface for computational imaging.
Sustainable active light modulation with atomically thin nanophotonic devices and computation imaging. a, Nanoelectromechanical system (NEMS) plasmonic dimer light modulator with sub-nanometer gap. b, Solid-state free-space light modulator with two-dimensional semiconductor. c, Metasurface for computational imaging.

State-of-the-art characterization

One of our strategies to study and create new light-matter interactions is exploiting state-of-the-art technologies (e.g., in-situ TEM and conceptually new spectroscopy) and characterize the unexplored aspects of emerging materials and the performance of brand new functions which are, otherwise, hardly measurable.

Suggested readings

  • Nat. Nanotechnol. 16, 1224-1230 (2021).
  • Nat. Photonics 14, 426-430 (2020).
  • Nat. Commun. 12, 1-7 (2021).
Cutting-edge characterization of optical materials and structures at atomic scale. a, Spectroscopic light scattering properties of two-dimensional semiconductor. b, In-situ electron energy lose spectroscopy (EELS) of sub-nanometer gap nano-plasmonic dimer in a transmission electron microscope (TEM). c, Angle-resolved spectroscopy of 3-nm-thin Si grating on a dielectric thin film.
Cutting-edge characterization of optical materials and structures at atomic scale. a, Spectroscopic light scattering properties of two-dimensional semiconductor. b, In-situ electron energy lose spectroscopy (EELS) of sub-nanometer gap nano-plasmonic dimer in a transmission electron microscope (TEM). c, Angle-resolved spectroscopy of 3-nm-thin Si grating on a dielectric thin film.