In-fber whispering gallery mode(WGM)microsphere resonators have received remarkable attention due to the superiorities of compact structure,high stability and self-alignment.As an in-fber structure,WGM microsphere res...In-fber whispering gallery mode(WGM)microsphere resonators have received remarkable attention due to the superiorities of compact structure,high stability and self-alignment.As an in-fber structure,WGM microsphere resonators have been demonstrated in various applications,such as sensors,flters and lasers,which have signifcant impacts on modern optics.Herein,we review recent progress of in-fber WGM microsphere resonators,which involve fbers of diverse structures and microspheres of diferent materials.First,a brief introduction is given to in-fber WGM microsphere resonators,from structures to applications.Then,we focus on recent progresses in this feld,including in-fber couplers based on conventional fbers,capillaries and micro-structure hollow fbers,and passive/active microspheres.Finally,future developments of the in-fber WGM microsphere resonators are envisioned.展开更多
In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, cont...In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, contrast, and width of the Fano resonance are analyzed. As the transmission coefficient of the capillary resonator increases, the absolute value of the slope of Fano resonances increases to reach its maximum, which is useful for sensors with an ultra-high sensitivity. There occurs another phenomenon of electromagnetically induced transparency when the reflectivity at the capillary–environment interface is close to 100%. We also experimentally demonstrated its capability for temperature and refractive index sensing, with a sensitivity of 10.9 pm∕°C and 431 d B∕RIU basedon the Fano resonance and the Lorentzian line shape, respectively.展开更多
We proposed a two-coupled microsphere resonator structure as the element of angular velocity sensing under the Sagnac effect.We analyzed the theoretical model of the two coupled microspheres,and derived the coupled-re...We proposed a two-coupled microsphere resonator structure as the element of angular velocity sensing under the Sagnac effect.We analyzed the theoretical model of the two coupled microspheres,and derived the coupled-resonatorinduced transparency（CRIT） transfer function,the effective phase shift,and the group delay.Experiments were also carried out to demonstrate the CRIT phenomenon in the two-coupled microsphere resonator structure.We calculated that the group index of the two-coupled sphere reaches n_g = 180.46,while the input light at a wavelength of 1550 nm.展开更多
We report the fabrication and optical characterization of spherical whispering gallery mode(WGM) resonators made from ultraviolet(UV)-curable adhesive. The fabricated microspheres have good sphericity and surface smoo...We report the fabrication and optical characterization of spherical whispering gallery mode(WGM) resonators made from ultraviolet(UV)-curable adhesive. The fabricated microspheres have good sphericity and surface smoothness, and can directly adhere to the tip of half-tapered fibers for easy manipulation. WGMs are e?ciently excited in the microsphere using an evanescent field of the tapered silica optical fibers. Resonances with quality factors of 1.3×10 5 are observed. The dependence of wavelength shifts of WGM resonances on the input light powers shows that the resonant wavelength of the proposed microsphere resonators can be tuned thermo-optically.展开更多
Conventionally, metallic nanostructures are used for surface-enhanced Raman spectroscopy(SERS), but recently there has been increasing interest in the enhancement of Raman scattering from dielectric substrates due to ...Conventionally, metallic nanostructures are used for surface-enhanced Raman spectroscopy(SERS), but recently there has been increasing interest in the enhancement of Raman scattering from dielectric substrates due to their improved stability and biocompatibility compared with metallic substrates. Here, we report the observation of enhanced Raman scattering from rhodamine 6 G molecules coated on silica microspheres. We excite the whispering gallery modes(WGMs) supported in the microspheres with a tapered fiber coupler for efficient WGM excitation, and the Raman enhancement can be attributed to the WGM mechanism. Strong resonance enhancement in pump laser intensity and modified Raman emission from the Purcell effect in the microsphere resonator are observed from the experiment and compared with theoretical results. A total Raman enhancement factor of 1.4 × 10~4 is observed, with contribution mostly from the enhancement in pump laser intensity. Our results show that, with an efficient pumping scheme, dielectric microspheres are a viable alternative to metallic SERS substrates.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFF0708400)the National Natural Science Foundation of China(NSFC)(Grant Nos.62022053,61875116,and 62205192)+3 种基金the 111 Project(D20031)the Advanced Optical Waveguide Intelligent Manufacturing and Testing Professional Technical Service Platform of Shanghai(19 DZ2294000)the Open Project Program of Wuhan National Laboratory for Optoelectronics(2021WNLOKF002)the Science and Technology Commission of Shanghai Municipality Project Grant(22010500100,22ZR1424800).
文摘In-fber whispering gallery mode(WGM)microsphere resonators have received remarkable attention due to the superiorities of compact structure,high stability and self-alignment.As an in-fber structure,WGM microsphere resonators have been demonstrated in various applications,such as sensors,flters and lasers,which have signifcant impacts on modern optics.Herein,we review recent progress of in-fber WGM microsphere resonators,which involve fbers of diverse structures and microspheres of diferent materials.First,a brief introduction is given to in-fber WGM microsphere resonators,from structures to applications.Then,we focus on recent progresses in this feld,including in-fber couplers based on conventional fbers,capillaries and micro-structure hollow fbers,and passive/active microspheres.Finally,future developments of the in-fber WGM microsphere resonators are envisioned.
基金National Natural Science Foundation of China(NSFC)(61377081,61675126)
文摘In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, contrast, and width of the Fano resonance are analyzed. As the transmission coefficient of the capillary resonator increases, the absolute value of the slope of Fano resonances increases to reach its maximum, which is useful for sensors with an ultra-high sensitivity. There occurs another phenomenon of electromagnetically induced transparency when the reflectivity at the capillary–environment interface is close to 100%. We also experimentally demonstrated its capability for temperature and refractive index sensing, with a sensitivity of 10.9 pm∕°C and 431 d B∕RIU basedon the Fano resonance and the Lorentzian line shape, respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51225504,61171056,and 91123036)the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province,China
文摘We proposed a two-coupled microsphere resonator structure as the element of angular velocity sensing under the Sagnac effect.We analyzed the theoretical model of the two coupled microspheres,and derived the coupled-resonatorinduced transparency（CRIT） transfer function,the effective phase shift,and the group delay.Experiments were also carried out to demonstrate the CRIT phenomenon in the two-coupled microsphere resonator structure.We calculated that the group index of the two-coupled sphere reaches n_g = 180.46,while the input light at a wavelength of 1550 nm.
基金supported by the National Natural Science Foundation of China(No.61275050)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20120121110034)the Fundamental Research Funds for the Central Universities of Xiamen University(Nos.2010121059 and 2011121048)
文摘We report the fabrication and optical characterization of spherical whispering gallery mode(WGM) resonators made from ultraviolet(UV)-curable adhesive. The fabricated microspheres have good sphericity and surface smoothness, and can directly adhere to the tip of half-tapered fibers for easy manipulation. WGMs are e?ciently excited in the microsphere using an evanescent field of the tapered silica optical fibers. Resonances with quality factors of 1.3×10 5 are observed. The dependence of wavelength shifts of WGM resonances on the input light powers shows that the resonant wavelength of the proposed microsphere resonators can be tuned thermo-optically.
基金National Science Foundation(NSF)(CBET1264750,CBET 1264997)Army Research Office(ARO)(W911NF-16-1-0339)
文摘Conventionally, metallic nanostructures are used for surface-enhanced Raman spectroscopy(SERS), but recently there has been increasing interest in the enhancement of Raman scattering from dielectric substrates due to their improved stability and biocompatibility compared with metallic substrates. Here, we report the observation of enhanced Raman scattering from rhodamine 6 G molecules coated on silica microspheres. We excite the whispering gallery modes(WGMs) supported in the microspheres with a tapered fiber coupler for efficient WGM excitation, and the Raman enhancement can be attributed to the WGM mechanism. Strong resonance enhancement in pump laser intensity and modified Raman emission from the Purcell effect in the microsphere resonator are observed from the experiment and compared with theoretical results. A total Raman enhancement factor of 1.4 × 10~4 is observed, with contribution mostly from the enhancement in pump laser intensity. Our results show that, with an efficient pumping scheme, dielectric microspheres are a viable alternative to metallic SERS substrates.
