Xiao-Cong Yuan - Biograph#
For over three decades, Professor Yuan has dedicated his expertise to the field of nanophotonics, contributing over 500 publications to esteemed journals, including Science, Nature Physics, Nature Communications, Science Advances, Physical Review Letters, and PNAS, among others. His research covers pioneering topics such as orbital angular momentum multiplexing communication technology and high-sensitivity sensing and imaging methodologies.
Contributions to studies of optical singularities and matter interactions at the nanoscale:
The optical singularities, encompassing phase and polarization singularities, exhibit intriguing properties such as orbital angular momentum, integer quantization, nondiffracting behavior, and small scale characteristics. These attributes have been instrumental in exploring light-matter interactions at the nanoscale and advancing the development of nano-plasmonics over the past three decades. Professor Yuan established the internationally renowned Nanophotonics Research Centre at Shenzhen University, recognized by the Nature Index as the primary contributor to the weighted fractional count index of physical sciences in Shenzhen City. Under his leadership, his team has developed a new theoretical framework and innovative methodologies that intricately control the dynamics of singular optical fields. A review detailing the progress of singular optics and optical singularities-matter interactions at the nanoscale was published in "Optical vortices 30 years on: OAM manipulation from topological charge to multiple singularities, Light: Science & Applications 8(1), 90 (2019)".
The achievements can be summarized as follows: Initially, through an exploration of chiral light-nanoantenna interactions, a pioneering methodology was introduced to selectively induce optical helical states using artificial nanostructures. Subsequently, by investigating and refining the weak and strong couplings within chiral light-nanoantenna arrays, an exceptionally broad-band chirality response was attained within metasurface structures. These advancements hold promise for applications in chiral detection and sensing. Further investigations into the interplay between polarization singularities and nanostructures led to the development of stable optical tweezers for manipulating mesoscopic metal particles, as showcased in Nature Communications. The team extended the applications of these plasmonic optical tweezers to include edge detection for two-dimensional (2D) materials and nanoscale surface-enhanced Raman spectroscopy imaging of biomolecules. Recently, an unprecedented discovery of topological optical spin-vortex structures, akin to skyrmions in magnetism, was made. These photonic Skyrmions exhibit unified topological properties, with stable spin states transitioning between 'up/down' and 'down/up' states, resilient to disturbances. Additionally, they feature intricate spin fine structures at deep-subwavelength scales, rendering them advantageous for subwavelength imaging and picometer-scale metrology. Maxwell-like spin-momentum equations were formulated, offering a framework to explore the dynamic properties of optical fields at the nanoscale and paving the way for manipulating chiral matter through lateral optical forces arising from Poynting momentum vorticities. This pioneering research has been published in prestigious journals such as Nature Physics, PNAS, and Physical Review Letters (PRL).
Contributions to study of mode multiplexing mechanism for optical interconnection:
In response to the urgent demand for advanced optical interconnection solutions in the realm of High-Performance Computing (HPC), Professor Yuan's team has introduced a groundbreaking concept: optical vortex mode multiplexing communication, thereby heralding a new era with the introduction of the singular vector field. The primary aim was to address the three core challenges encountered in optical vortex multiplexing: limited capacity, compatibility, and transmission robustness.
In high-capacity OAM multiplexing communication, the traditional mode multiplexer faces limitations in the number of channels it can multiplex. Adding more modes leads to a sharp decrease in conversion efficiency of higher-order modes, constraining the multiplexed channels and communication capacity. Professor Yuan's team has introduced a novel mechanism for finely-tuned orbital angular momentum (OAM) beams through sub-cycle precision structure modulation. They have successfully achieved parallel detection of co-axial multi-channel multiplexed OAM signals, overcoming the bottleneck in the number of OAM multiplexed channels and information capacity. Collaborating with Huawei's pre-research department, Professor Yuan demonstrated simultaneous multiplexing and demultiplexing of 10 independent OAM channels, compatible with 80-channel wavelength division multiplexing and 2-channel polarization multiplexing, setting a record of 160 Tbit/s ultra-high-speed free-space optical communication at the time. Subsequently, the team utilized two-photon polymerization 3D micro-nano fabrication technology to integrate the vortex Dammann grating into the end face of optical fibers for optical vortex multiplexing communication, further enhancing the communication capacity density of a single optical fiber. These high-capacity solutions have garnered widespread attention and recognition in the optical communications field, with the paper receiving a distinguished Excellent Paper Award from the China Association for Science and Technology. Additionally, the related core technology patent (ZL201410230735.3) was honored with the "Outstanding Award" in the 20th China Patent Awards in 2018.
In the realm of mode-division multiplexed integrated optical communication, the conventional micro-resonator structure mode emitter exhibits a narrow bandwidth and lacks compatibility with wavelength division multiplexing technology. Moreover, its optical field modulation mechanism fails to generate multiple OAM (Orbital Angular Momentum) modes. In response to these compatibility issues and challenges, Professor Yuan's team has introduced a novel mechanism grounded in the reverse design of silicon-based metasurfaces. This mechanism amalgamates the propagation path and coupling resonance for joint phase modulation, effectively yielding a wideband OAM beam multiplexer spanning the C+L+S full communication band from 1450 nm to 1650 nm, with an impressive conversion efficiency of up to 35%. By integrating this mechanism with a 30-channel optical frequency comb multiplexer, they have realized a remarkable communication capacity of 1.2 Tbit/s. This innovation presents a pragmatic solution for high-capacity density integrated optical communication that aligns with wavelength division multiplexing in the forthcoming generation of data centers and high-performance computers.
Cylindrical vector beams (CVBs) are the eigenmodes of optical fibers, renowned for their robust stability during fiber transmission. These CVBs, with their mutually orthogonal nature across different orders, introduce a novel and dependable multiplexing transmission mechanism for mode-division multiplexed communication. Addressing the pivotal challenge of CVB demultiplexing, Professor Yuan's team has pioneered a new demultiplexing mechanism founded on spin-correlated anisotropic optical geometric transformation, tailored for multi-channel coaxial CVB demultiplexing. Utilizing a CVB demultiplexer crafted with photo-aligned liquid crystals, they have realized the demultiplexing communication of 21 CVB modes, achieving an average demultiplexing efficiency of up to 61.7%. In the realm of integrated CVB multiplexing and demultiplexing, this innovative approach seamlessly integrates lambda-shaped metallic nanoslit units with a spin Hall response onto a series of asymmetric surface plasmon resonance grating structures. This integration facilitates the simultaneous demodulation of vector vortex modes carrying diverse phase and polarization singularities, thereby meeting the stringent demands of modern optical communication systems for compact size, affordability, and high data rates.
