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McKelvey School of Engineering

ESE Seminar: Preliminary Oral Exam Zhoutian Fu

Tuesday, January 19 | 3:00 PM - 5:00 PM

 The concept of radiation pressure of light was first put forward by Kelper to explain why comet tail always points away from the sun. It was later modelled by Maxwell’s theory and experimentally confirmed in 1901. With the development of lasers in 1960s, the light radiation pressure in Fabry-Perot cavities can be strong enough to alter the mechanical dynamics of cavity mirror. The study on the coupling between optical modes and mechanical modes mediated by radiation pressure was called cavity optomechanics. In the recent decades, optical whispering-gallery-mode (WGM) microresonators prove to be an ideal candidate for the study of cavity optomechanics, due to their ultrahigh quality-factors, confined mode volume, small effective mass and great flexibility of system parameters. Many fundamental studies and interesting applications have been demonstrated in this platform, such as resolved-sideband cooling, optomechanical sensors, synchronization, phonon lasers and chaos transfer.


In this presentation, I will introduce the novel phenomenon of cavity optomechanics solitons, and propose several applications related to the cavity optomechanical effects in WGM microresonators. First, I will introduce the model for mechanical solitons under optomechanically induced nonlinearity and dispersion. The dynamics of the mechanical travelling wave turns out to resemble the celebrated Korteweg-de Vires equation, which can form soliton and cnoidal-wave. Several problems related to the physical essence of the mechanical solitons are explored, such as parameter-dependence of the cnoidal-wave, different dynamical regimes and interaction of multiple solitons. Second, the applications of mechanical solitons are proposed together with preliminary data, including optomechanical combs and soliton-assist low-frequency detection. Third, I will talk about optomechanically enhanced sensing in WGM microresonators. Besides optical resonance amplification, the mechanical resonance effect serves as another mechanism to enhance the sensor response to signals with close frequency, such as photoacoustic signals

Event Type



McKelvey School of Engineering


Science & Technology

Electrical & Systems Engineering
Speaker Information

Zhoutian Fu
PhD Candidate
Washington University in St. Louis 

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