| Biography | |
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 Prof. Hairun Guo Shanghai University, China |
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| Title: Response of vector supercontinuum in photonic waveguides | |
| Abstract: Supercontinuum generation has been well known for extending the bandwidth of mode locked lasers to perform f-2f self-referencing[1]. Recently, this process in photonic integrated platforms has also been employed to access optical frequency combs in the mid-infrared[2,3] as well as in the visible, with demonstrated no degradation in the coherence. Conventionally, the supercontinuum process is managed within one of the two fundamental x- and y-polarized modes in a photonic waveguide. In this talk, we will review our recent advances in photonic supercontinuum serving for coherent and broadband mid-infrared optical frequency combs, including a proof-of-concept mid-infrared dual-comb spectrometer[3]. More importantly, we will report a novel photonic supercontinuum dynamic that involves both of the two fundamental modes of the waveguide. We discover that in addition to simultaneous supercontinuum generations in both modes, light coupling is featured as a transfer function in the radio frequency (rf) domain, and a response spectrum in the optical domain can be retrieved. Remarkably, the coupling response is coherently transferred within the entire supercontinuum, which can be detected in e.g. the visible range where high-sensitive and low-noise detectors are available. Physically, the retrieved response spectrum reveals a complete chart of wavelength-dependent coupling intensities in the photonic waveguide. Given the fact that two fundamental modes are orthogonal polarized, we term our observation as a vector supercontinuum process. References: [1] D. J. Jones, et al., "Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis," Science 288(5466), 635–639 (2000). [2] H. Guo, et al., "Mid-infrared frequency comb via coherent dispersive wave generation in silicon nitride nanophotonic waveguides," Nat. Photon. 12(6), 330 (2018). [3] H. Guo, et al., "Nanophotonic supercontinuum-based mid-infrared dual-comb spectroscopy," Optica 7(9), 1181 (2020). | |
| Biography: Dr. Guo obtained his Bachelor and Master degree at Shanghai University, Shanghai, China, in 2008 and 2011, respectively. In 2011, he started his PhD study at Technical University of Denmark (DTU), Denmark, where he joined the group of Ultrafast Nonlinear Optics (UNO) lead by Prof. Morten Bache. His PhD topic was “cascaded quadratic soliton compression in waveguide structures” which includes the near-infrared and mid-infrared soliton pulse formation, and soliton induced supercontinuum generations, as well as light-matter interactions in nonlinear crystals and crystal waveguides. He defended his PhD thesis and obtained the degree in 2014. Since 2015, he joined the Kippenberg Laboratory (Laboratory of Photonics and Quantum Measurements, LPQM) atSwiss Federal Institute of Technology Lausanne (EPFL), Switzerland, and embarked on a new phase of his career as a postdoctoral scientist. His research interests were centered on microresonator based optical frequency combs andcavity dissipative soliton physics, with a focus on mid-infrared frequency comb generations in nano-photonic chip-based devices. In 2019, he received a professorship in Photonics Engineering at Shanghai University (Shanghai, China) where now he is building up his own lab. His group will focus on the topic of optical frequency combs and ultra-fast nonlinear regimes in optical frequency metrology. | |
