[1] Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA
[2] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA
[3] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
[4] Univ Munich, Dept Chem, D-81377 Munich, Germany
[5] Schlumberger EPS, SRPC, F-92142 Clamart, France
[6] Sabanci Univ, Fac Engn & Nat Sci, Istanbul, Turkey
[7] ETH Honggerberg, Inst Quantum Elect, CH-8083 Zurich, Switzerland