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Chinese Science Bulletin, Volume 65 , Issue 27 : 3028-3042(2020) https://doi.org/10.1360/TB-2020-0333

Research advances of ultrahigh-Q on-chip microcavity photonics

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  • ReceivedMar 28, 2020
  • AcceptedMay 21, 2020
  • PublishedMay 22, 2020

Abstract


Funding

国家杰出青年科学基金(11825402)


Author information

肖云峰, 北京大学博雅特聘教授、长江特聘教授、美国光学学会会士, 主要从事超高品质因子光学微腔研究. 近年来, 成果两次入选“中国高校十大科技进展”, 四次入选“中国光学十大进展”.


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  • Figure 1

    Schemitic illustration of whispering gallery mode (WGM). (a) Light ray propagates along the surface inside the cavity by total internal reflectioin. (b) Echo wall at Temple of Heaven in Beijing (image from internet). (c) Typical electric field distribution of optical WGM (clockwise)

  • Figure 2

    On-chip WGM microlasers. (a) Erbium-doped microtoroid laser[7]. (b) CdSe/ZnS quantum-dots (QDs)-coated toriod microlaser[8]. The left panel is the scanning electron micrograph (SEM) of the microlaser, and the right panel is the optical micrograph of the microlaser with light emission under the pump. (c) InAs/GaAs semiconductor QD microdisk laser with ultra-low threshold under the continuous-wave pump at room temperature[9]. (d) Unidirectional emission of WGM microlaser[10]. (e) Orbital angular momentum WGM microlaser[11]

  • Figure 3

    Typical nonlinear optical effects in on-chip WGM microcavities. (a) Raman laser spectrum in a silica microtoroid[39]. Inset: The sideview of the microcavity used in the experiment. (b) Back-spectrum of stimulated Brillouin scattering in a silica microdisk[40]. (c) Optical spectra of third harmonic generation in a silicon nitride microring[42]. Inset: Topview image of the microring with third harmonic light. (d) Ultra-broadband microcomb generation in a silica asymmetric microtoroid by combining multiple nonlinear effects including four-wave mixing, third-order sum frequency generation, symetry-breaking induced second-order sum frequency generation[45]. Inset: Multi-color light emission image observed by an optical microscope

  • Figure 4

    Application areas of microcombs[78]. From top, clockwise: Ultrafast distance measurements (LIDAR), optical atomic clocks, photonic radar, dual-comb spectroscopy, optical coherence tomography, low-noise microwaves, optical frequency synthesizer, astronomical spectrometer calibration, and coherent communications

  • Figure 5

    Applications of on-chip microcavities in photonic integrated circuits. (a) Monolithic lithium niobate photonic circuits[83], where lithium niobite microring cavities are used for multifunctional devices, including the generation of microcombs light source, optical filtering, electrooptical modulation. (b) Silica microtoroid with add-drop coupling structure for optical filter[84]. Port 1 is input, and port 4 is output. (c) Optical isolator by using optothermal effect and asymmetric coupling in silicon microrings (the coupling gaps at G2 and G3 are different)[59]. (d) Nonlinear strong couling and nonreciprocal light propagation by second-order sum frequency generation effect in an aluminium nitride microring[58]. (e) On-chip electro-optic modulators by Pockel effect in lithium niobite race-track and microring cavities[56]. (f) Ultra-broadband coupling in the asymmetric microcavity-nanowaguide system[85]

  • Figure 6

    Single nanoparticle detection with the WGM sensor. When a nanoparticle approaches to the WGM cavity, the mode variation can represent as mode shift (a)[107], mode splitting (b)[108], or mode broadening (c)[109]

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