On-chip ultrahigh-Q microcavities for highly unidirectional emission

Optical whispering gallery mode (WGM) microcavities are promising candidates for basic research and optoelectronic applications. Due to the isotropic emission property resulting from the rotational symmetry, traditional WGM microcavities have to rely on external couplers to excite the modes and collect their emission. One of the most possible solutions is to deform microcavities from rotational symmetry, which could provide directional emission instead of isotropic characteristic. Here we report the first experimental realization of on-chip microcavities which support both highly unidirectional emission and ultra-high Q factors. The demonstrated Q factor exceeds 100 million in near infrared. By doping erbium into the deformed microcavity, lasing action in 1550 nm band was observed under convenient freespace optical pumping, with the threshold as low as 2 μW. Remarkably, the lasing emission is along a single direction with a narrow divergence angle about 10 degrees.

[1]  G. Guo,et al.  Low-threshold microlaser in a high-Q asymmetrical microcavity. , 2009, Optics letters.

[2]  A. Stone,et al.  Ray and wave chaos in asymmetric resonant optical cavities , 1997, Nature.

[3]  J. Knight,et al.  Phase-matched excitation of whispering-gallery-mode resonances by a fiber taper. , 1997, Optics letters.

[4]  Federico Capasso,et al.  Directional emission and universal far-field behavior from semiconductor lasers with limaçon-shaped microcavity , 2009 .

[5]  A. F. J. Levi,et al.  Whispering-gallery mode microdisk lasers , 1992 .

[6]  Richard K. Chang,et al.  Unidirectional lasing from InGaN multiple-quantum-well spiral-shaped micropillars , 2003 .

[7]  Jan Wiersig,et al.  Combining directional light output and ultralow loss in deformed microdisks. , 2007, Physical review letters.

[8]  S. Arnold,et al.  Whispering-gallery-mode biosensing: label-free detection down to single molecules , 2008, Nature Methods.

[9]  Sang Wook Kim,et al.  Observation of scarred modes in asymmetrically deformed microcylinder lasers. , 2001, Physical review letters.

[10]  Hailin Wang,et al.  Directional tunneling escape from nearly spherical optical resonators. , 2003, Physical review letters.

[11]  Kerry J. Vahala,et al.  Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process , 2005 .

[12]  T. Kippenberg,et al.  Cavity Optomechanics: Back-Action at the Mesoscale , 2008, Science.

[13]  Lute Maleki,et al.  Nonlinear optics and crystalline whispering gallery mode cavities. , 2004, Physical review letters.

[14]  Oskar Painter,et al.  Actuation of micro-optomechanical systems via cavity-enhanced optical dipole forces , 2007 .

[15]  H. J. Kimble,et al.  Trapping of Single Atoms in Cavity QED , 1999 .

[16]  Lan Yang,et al.  Highly Unidirectional Emission and Ultralow‐Threshold Lasing from On‐Chip Ultrahigh‐Q Microcavities , 2012, Advanced materials.

[17]  S. Sunada,et al.  Asymmetric stationary lasing patterns in 2D symmetric microcavities. , 2003, Physical review letters.

[18]  Federico Capasso,et al.  Whispering-gallery mode resonators for highly unidirectional laser action , 2010, Proceedings of the National Academy of Sciences.

[19]  K. Vahala.  Optical microcavities , 2003, Nature.

[20]  Soo-Young Lee,et al.  Pump-induced dynamical tunneling in a deformed microcavity laser. , 2010, Physical review letters.

[21]  Yan Li,et al.  Strongly enhanced light-matter interaction in a hybrid photonic-plasmonic resonator , 2012, 1206.2422.

[22]  Cho,et al.  High-power directional emission from microlasers with chaotic resonators , 1998, Science.

[23]  T. J. Kippenberg,et al.  Ultra-high-Q toroid microcavity on a chip , 2003, Nature.

[24]  Zheng-Fu Han,et al.  Directional escape from a high-Q deformed microsphere induced by short CO2 laser pulses. , 2007, Optics letters.

[25]  G. Guo,et al.  Mechanism of unidirectional emission of ultrahigh Q Whispering Gallery mode in microcavities , 2009, 0908.3531.

[26]  Vladimir S. Ilchenko,et al.  Quality-factor and nonlinear properties of optical Whispering-Gallery modes , 1989 .

[27]  Lan Yang,et al.  On-chip single nanoparticle detection and sizing by mode splitting in an ultrahigh- Q microresonator , 2010 .

[28]  Zheng-Fu Han,et al.  High-Q exterior whispering-gallery modes in a metal-coated microresonator. , 2010, Physical review letters.