Paul E. Barclay

Nonlinear response of silicon photonic crystal microresonators excited via an integrated waveguide and fiber taper

A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a high-Q, ultra-small mode volume, silicon photonic crystal resonant cavity. Cavity mode quality factors of 4.7x10(4) are measured, and a total fiber-to-cavity coupling efficiency of 44% is demonstrated. Using this efficient cavity input and output channel, the steady-state nonlinear absorption and dispersion of the photonic crystal cavity is studied. Optical bistability is observed for fiber input powers as low as 250 microW, corresponding to a dropped power of 100 microW and 3 fJ of stored cavity energy. A high-density effective free-carrier lifetime for these silicon photonic crystal resonators of ~ 0.5 ns is also estimated from power dependent loss and dispersion measurements.

Diamonds with a high density of nitrogen-vacancy centers for magnetometry applications

V. M. Acosta, E. Bauch, 2 M. P. Ledbetter, C. Santori, K.-M. C. Fu, P. E. Barclay, R. G. Beausoleil, H. Linget, J. F. Roch, F. Treussart, S. Chemerisov, W. Gawlik, and D. Budker 8, 9 1 Department of Physics, University of California, Berkeley, CA 94720-7300 2 Technische Universität Berlin, Hardenbergstraÿe 28, 10623 Berlin, Germany 3 Hewlett-Packard Laboratories, 1501 Page Mill Rd., Palo Alto, CA 94304 4 Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan CEDEX, France 5 Laboratoire de Photonique Quantique et Moléculaire (CNRS UMR 8537), Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan CEDEX, France 6 Argonne National Laboratory, Argonne, IL, 60439, U.S.A. 7 Center for Magneto-Optical Research, Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA budker@berkeley.edu (Dated: July 31, 2009)

Experimental demonstration of a high quality factor photonic crystal microcavity

Subthreshold measurements of a photonic crystal (PC) microcavity laser operating at 1.3 μm show a linewidth of 0.10 nm, corresponding to a quality factor (Q)∼1.3×104. The PC microcavity mode is a donor-type mode in a graded square lattice of air holes, with a theoretical Q∼105 and mode volume Veff∼0.25 cubic half-wavelengths in air. Devices are fabricated in an InAsP/InGaAsP multi-quantum-well membrane and are optically pumped at 830 nm. External peak pump power laser thresholds as low as 100 μW are also observed.

Chip-based microcavities coupled to nitrogen-vacancy centers in single crystal diamond

Optical coupling of nitrogen-vacancy centers in single-crystal diamond to an on-chip microcavity is demonstrated. The microcavity is fabricated from a hybrid gallium phosphide and diamond material system and supports whispering gallery mode resonances with spectrometer resolution limited Q>25 000.

Conversion of neutral nitrogen-vacancy centers to negatively charged nitrogen-vacancy centers through selective oxidation

The conversion of neutral nitrogen-vacancy centers to negatively charged nitrogen-vacancy centers is demonstrated for centers created by ion implantation and annealing in high-purity diamond. Conversion occurs with surface exposure to an oxygen atmosphere at 465 °C. The spectral properties of the charge-converted centers are investigated. Charge state control of nitrogen-vacancy centers close to the diamond surface is an important step toward the integration of these centers into devices for quantum information and magnetic sensing applications.

Rayleigh scattering, mode coupling, and optical loss in silicon microdisks

High refractive index contrast optical microdisk resonators fabricated from silicon-on-insulator wafers are studied using an external silica fiber taper waveguide as a wafer-scale optical probe. Measurements performed in the 1500 nm wavelength band show that these silicon microdisks can support whispering-gallery modes with quality factors as high as 5.2×10^5, limited by Rayleigh scattering from fabrication induced surface roughness. Microdisks with radii as small as 2.5 µm are studied, with measured quality factors as high as 4.7×10^5 for an optical mode volume of 5.3 (lambda/n)^3.

Experimental demonstration of fiber-accessible metal nanoparticle plasmon waveguides for planar energy guiding and sensing

Experimental evidence of mode-selective evanescent power coupling at telecommunication frequencies with efficiencies up to 75% from a tapered optical fiber to a metal nanoparticle plasmon waveguide is presented. The waveguide consists of a two-dimensional square lattice of lithographically defined Au nanoparticles on an optically thin silicon membrane. The dispersion and attenuation properties of the waveguide are analyzed using the fiber taper. The high efficiency of power transfer into these waveguides solves the coupling problem between conventional optics and plasmonic devices and could lead to the development of highly efficient plasmonic sensors and optical switches.

Optical-fiber-based measurement of an ultrasmall volume high-Q photonic crystal microcavity

A two-dimensional photonic crystal semiconductor microcavity with a quality factor

Coherent interference effects in a nano-assembled diamond NV center cavity-QED system.

Q\ensuremath{\sim}40,000

Nanophotonics for quantum optics using nitrogen-vacancy centers in diamond

and a modal volume