Publication

Chaos-assisted broadband momentum transformation in optical microresonators

Xuefeng Jiang, Linbo Shao, Shu-Xin Zhang, Xu Yi, Jan Wiersig, Li Wang, Qihuang Gong, Marko Lončar, Lan Yang, and Yun-Feng Xiao, Science 358, 344 (2017).

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The law of momentum conservation rules out many desired processes in optical microresonators. We report broadband momentum transformations of light in asymmetric whispering gallery microresonators. Assisted by chaotic motions, broadband light can travel between optical modes with different angular momenta within a few picoseconds. Efficient coupling from visible to near-infrared bands is demonstrated between a nanowaveguide and whispering gallery modes with quality factors exceeding 10 million. The broadband momentum transformation enhances the device conversion efficiency of the third-harmonic generation by greater than three orders of magnitude over the conventional evanescent-wave coupling. The observed broadband and fast momentum transformation could promote applications such as multicolor lasers, broadband memories, and multiwavelength optical networks.


Experimental demonstration of spontaneous chirality in a nonlinear microresonator

Qi-Tao Cao, Heming Wang, Chun-Hua Dong, Hui Jing, Rui-Shan Liu, Xi Chen, Li Ge, Qihuang Gong, and Yun-Feng Xiao, Phys. Rev. Lett 118, 033901 (2017)., Highlighted in Phys. org, Photonics Online

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Chirality is an asymmetric property widely found in nature. Here, we propose and demonstrate experimentally the spontaneous emergence of chirality in an on-chip ultrahigh- Q whispering-gallery microresonator, without broken parity or time-reversal symmetry. This counterintuitive effect arises due to the inherent Kerr-nonlinearity-modulated coupling between clockwise and counterclockwise propagating waves. Above an input threshold of a few hundred microwatts, the initial chiral symmetry is broken spontaneously, and the counterpropagating output ratio exceeds 20 ∶ 1 with bidirectional inputs. The spontaneous chirality in an on-chip microresonator holds great potential in studies of fundamental physics and applied photonic devices.


Single Nanoparticle Detection and Sizing Using a Nanofiber Pair in an Aqueous Environment

Xiao-Chong Yu, Bei-Bei Li, Pan Wang, Limin Tong, Xue-Feng Jiang, Yan Li, Qihuang Gong and Yun-Feng Xiao, Advanced Materials 26(44), 7462-7467 (2014). Front cover paper, highlighted in Materials Views, AZO nano.

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Optical fiber sensors have been extensively employed in high-sensitivity biosensing, due to their advantages of simple configuration, low cost, label-free property, and remote sensing capability. Over the past few years, it has been demonstrated that when the diameter of fiber is reduced to the scale of optical wavelength, there exists pronounced evanescent field outside the nanofiber, which is very sensitive to the refractive index change of the surrounding medium. In this work, we fabricated a pair of nanofibers with uniform diameter, and placed them into a microfluidic channel. When single nanoparticles in the microfluidic channel are bound to the surface of the nanofibers, the transmitted power shows a significant decrease due to the scattering and absorption of the nanoparticles in the evanescent field. By monitoring the step changes in the transmission of the nanofiber, detection and sizing of nanoparticles with single uniform radius (~ \(100\) nm) and of mixed nanoparticles with two different radii (\(100\) nm and \(170\) nm) are both realized. Moreover, by employing plasmonic enhancement, detection of single gold nanorods with much smaller sizes (diameter ~ \(16\) nm, length ~ \(40\) nm), is also demonstrated. This nanofiber pair can be further extended to an array containing more nanofibers, thus to dramatically increase the sensing speed, which promises a bright future of the nanofiber sensors.


Single nanoparticle detection using split-mode microcavity Raman lasers

Bei-Bei Li, William R. Clements, Xiao-Chong Yu, Kebin Shi, Qihuang Gong, and Yun-Feng Xiao, PNAS 111(41), 14657-14662 (2014). Highlighted in Phys. org, Asian Scientist, and AZO nano.

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Ultrasensitive nanoparticle detection holds great potential for early-stage diagnosis of human diseases and for environmental monitoring. In this work, we report for the first time, to our knowledge, single nanoparticle detection by monitoring the beat frequency of split-mode Raman lasers in high-Q optical microcavities. We first demonstrate this method by controllably transferring single \(50\)-nm–radius nanoparticles to and from the cavity surface using a fiber taper. We then realize real-time detection of single nanoparticles in an aqueous environment, with a record low detection limit of \(20\) nm in radius, without using additional techniques for laser noise suppression. Because Raman scattering occurs in most materials under practically any pump wavelength, this Raman laser-based sensing method not only removes the need for doping the microcavity with a gain medium but also loosens the requirement of specific wavelength bands for the pump lasers, thus representing a significant step toward practical microlaser sensors.


Coherent Polariton Dynamics in Coupled Highly Dissipative Cavities

Yong-Chun Liu, Xingsheng Luan, Hao-Kun Li, Qihuang Gong, Chee Wei Wong, and Yun-Feng Xiao, Phys. Rev. Lett. 112(21), 213602 (2014). Highlighted in Phys. org, Photonics Online

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The coherent light-matter interaction at the single-photon and electronic qubit level promises to be a remarkable potential for nonclassical information processing. Besides the efforts of improving the figure of merit of the cavities, here we demonstrate strong anharmonicity in the polariton dressed states via dark state resonances in a highly dissipative cavity. It is shown that the vacuum Rabi oscillation occurs for a single quantum emitter inside a cavity even with the bosonic decay-to-interaction rate ratio exceeding \(10^2\), when the photon field is coupled to an auxiliary high-Q cavity. This study provides a promising platform for overcoming decoherence and advancing the coherent manipulation of polariton qubits.


Detection of Single Nanoparticles and Lentiviruses Using Microcavity Resonance Broadening

Linbo Shao, Xue-Feng Jiang, Xiao-Chong Yu, Bei-Bei Li, William R Clements, Frank Vollmer, Wei Wang, Yun-Feng Xiao, and Qihuangand Gong, Advanced Materials 25(39), 5616-5620 (2013). Frontispiece paper, Highlighted in materialsviews.com, materialsviewschina.com.

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A new label-free sensing mechanism is demonstrated experimentally by monitoring the whispering-gallery mode broadening in microcavities. It is immune to both noise from the probe laser and environmental disturbances, and is able to remove the strict requirement for ultra-high-Q mode cavities for sensitive nanoparticle detection. This ability to sense nanoscale objects and biological analytes is particularly crucial for wide applications.


Parametric Down-Conversion and Polariton Pair Generation in Optomechanical Systems

Yong-Chun Liu, Yun-Feng Xiao, You-Ling Chen, Xiao-Chong Yu, and Qihuang Gong, Phys. Rev. Lett. 111(8), 083601 (2013).

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We demonstrate that the nonlinear optomechanical interaction leads to parametric down-conversion, capable of generating polariton pairs formed by photons and phonons. The nonlinearity is resonantly enhanced through frequency matching, and such parametric down-conversion does not require the stringent condition that the single-photon optomechanical coupling strength g be on the order of the mechanical resonance frequency ωm. We provide analytical results for the frequency matching condition and derive the nonlinear coefficient. Numerical simulations on polariton pair generation are presented, showing that photon like polaritons, phononlike polaritons, and mixed photon-phonon polaritons can be selectively generated. Such nonlinear interaction offers a promising way for harnessing the optomechanical nonlinearity to manipulate photons and phonons.


Dynamic Dissipative Cooling of a Mechanical Resonator in Strong Coupling Optomechanics

Yong-Chun Liu, Yun-Feng Xiao, Xingsheng Luan, and Chee Wei Wong, Phys. Rev. Lett. 110(15), 153606 (2013).

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Cooling of mesoscopic mechanical resonators represents a primary concern in cavity optomechanics. In this Letter, in the strong optomechanical coupling regime, we propose to dynamically control the cavity dissipation, which is able to significantly accelerate the cooling process while strongly suppressing the heating noise. Furthermore, the dynamic control is capable of overcoming quantum backaction and reducing the cooling limit by several orders of magnitude. The dynamic dissipation control provides new insights for tailoring the optomechanical interaction and offers the prospect of exploring mesoscopic quantum physics.


Highly unidirectional emission and ultralow-threshold lasing from on-chip ultrahigh-Q microcavities

Xue-Feng Jiang, Yun-Feng Xiao, Chang-Ling Zou, Lina He, Chun-Hua Dong, Bei-Bei Li, Yan Li, Fang-Wen Sun, Lan Yang, and Qihuang Gong, Advanced Materials, 24(35), OP260 (2012). Highlighted in materialsviews.com, Optik & Photonik, and Optics and Photonics News.

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Ultrahigh-Q optical whispering gallery microcavities are promising platforms for fundamental studies and applied photonics. A new type of on-chip microcavity is experimentally realized, which supports both highly unidirectional emission and ultra-high-Q factors exceeding \(100\) million in near infrared. By doping erbium, the unidirectional-emission lasing is observed in \(1550\) nm band with the threshold as low as \(2\mu\)W.


High- Q Exterior Whispering-Gallery Modes in a Metal-Coated Microresonator

Yun-Feng Xiao, Chang-Ling Zou, Bei-Bei Li, Yan Li, Chun-Hua Dong, Zheng-Fu Han, and Qihuang Gong, Phys. Rev. Lett. 105(15), 153902 (2010). Highlighted in Optics and Photonics News.

We propose a kind of plasmonic whispering-gallery mode highly localized on the exterior surface of a metal-coated microresonator. This exterior (EX) surface mode possesses high quality factors at room temperature, and can be efficiently excited by a tapered fiber. The EX mode can couple to an interior (IN) mode and this coupling produces a strong anticrossing behavior, which not only allows conversion of IN to EX modes, but also forms a long-lived antisymmetric mode. As a potential application, the EX mode could be used for a biosensor with a sensitivity high of up to \(500\) nm per refraction index unit, a large figure of merit, and a wide detection range.

Paper Archive

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2008 and before

Books and Book Chapters

  • Yun-Feng Xiao, Xu-Bo Zou, Qihuang Gong, Guang-Can Guo, and Chee Wei Wong, “Quantum electrodynamics in photonic crystal nanocavities towards quantum information processing,” book chapter in Advances in Lasers and Electro Optics, IN -TECH, 2010.

Conference Contributions

  • Yun-Feng Xiao, "Raman lasing dynamics in split-mode microcavity and single-nanoparticle detection," in SPIE Photonics West (conference 9343), San Francisco, USA, Feb. 7-12, 2015 (invited).
  • Yun-Feng Xiao, "Induced transparency in optical whispering gallery microcavity systems," in SPIE Photonics West (conference 9378), San Francisco, USA, Feb. 7-12, 2015 (invited).
  • Xue-Feng Jiang, Linbo Shao, Qihuang Gong and Yun-Feng Xiao, “Ultrahigh-Q microcavities with highly directional emission,” in IEEE Photonics Conference, San Diego, USA, Oct. 12-16, 2014 (invited).
  • Yun-Feng Xiao, “Asymmetric whispering gallery microcavity optics and photonics,” in OSA Topical Conference: The 4th Advances in Optoelectronics and Micro/nano-optics, Xi’an, China, Sep. 17-20, 2014 (invited).
  • Yun-Feng Xiao, “Single nanoparticle detection using microcavity mode broadening,” in PIERS 2014, Guangzhou, China. Aug. 25-28, 2014 (invited).
  • Yun-Feng Xiao, “Single nanoparticle detection with mode splitting of the microcavity Raman lasers,” in The 4th International Conference on Optofluidics, Guangzhou, China, Aug. 28-30, 2014 (keynote).
  • Bei-Bei Li and Yun-Feng Xiao, “Single nanoparticle detection using high-Q microcavities,” in IPTA 2014, Beijing, China, May 13-15, 2014 (invited).
  • Yun-Feng Xiao, “Raman lasing dynamics in split-mode microcavity and single-nanoparticle detection,” in 560. WE-Heraeus Seminar - Taking Detection to the Limit: Biosensing with optical Microcavities, Bad Honnef, Germany, April 14-18, 2014 (invited).
  • Yun-Feng Xiao, "Detection of single nanoparticles and lentiviruses using microcavity mode broadening," in SPIE Photonics West (conference 8960), San Francisco, USA, Feb. 1-6, 2014 (invited).
  • Yun-Feng Xiao, "Ultrahigh-Q asymmetric microcavities and their applications," in NSFC-FRQNT workshop for optics, Canada, September 10-11, 2013 (invited).
  • Yun-Feng Xiao, "Real-time single-nanoparticle detection using subwavelength optical fiber," in The 3rd International Conference on Optofluidics, Hong Kong, P. R. China, Aug. 13-18, 2013 (invited).
  • Yun-Feng Xiao, "Chaos-assisted unidirectional lasing emission from an ultrahigh-Q whispering gallery microcavity," in The 15th International Conference on Transparent Optical Networks, Cartagena, Spain, June 23-27, 2013 (invited).
  • Yun-Feng Xiao, "Highly unidirectional emission from ultrahigh-Q microcavities on a silicon chip," in The 3rd International Workshop on Microcavities and Their Applications, Peking University, P. R. China, May 27-31, 2013 (invited).
  • Yun-Feng Xiao, "On-chip ultrahigh-Q microcavities for highly unidirectional emission," in SPIE Photonics West (Conference 8600), San Francisco, USA, Feb. 2-7, 2013 (invited).
  • Yun-Feng Xiao, "Optical microcavity sensing toward single-nanoparticle response," in NTU-PKU joint workshop for silicon photonics, Taipei, Dec 24-26, 2012 (invited).
  • Yun-Feng Xiao, "Highly unidirectional & ultralow-threshold lasing from on-chip ultrahigh-Q optical resonator," in Sino-UK Workshop on Nanophotonics and Metamaterials, Beijing, China, Dec. 6-8, 2012 (invited).
  • Yun-Feng Xiao, "Fano resonance in whispering gallery photonic microcavities," in SPIE Photonics Asia, Beijing, China, Nov. 5-7, 2012 (invited).
  • Yun-Feng Xiao, "Sensitivity enhancement and detection limit improvement in whispering gallery mode based biosensing," in The SPIE Defense, Security, and Sensing Conference, Baltimore, Maryland, April 22-27, 2012 (invited).
  • Yun-Feng Xiao, "Ultra-high-Q whispering gallery microresonators: Towards ultra-sensitive sensors and quantum-optical analogies," in The International Conference on Photonics Polymers / ICAPP-2011, Yokohama, Japan, December 1-2, 2011 (invited).
  • Yun-Feng Xiao, "Single nanoparticle detection with ultrahigh Q whispering gallery microresonator," in The 4th International Conference on Nanophotonics, Tsukuba, Japan, May 30 - June 3, 2010 (invited).
  • Yun-Feng Xiao, "Ultra-high-Q PDMS-based microresonators towards ultra-sensitive sensors and quantum-optical analogies, in OSA-COS Topical Meeting on Applications of Optical Metamaterials (AOM 2009)," Tianjin, P. R. China (invited).