Prof. Vahid Sandoghdar

  • Director
  • Head of Nano-Optics Division

The research of our group aims to advance experimental and theoretical mastery of light-matter interaction at the nanometer scale and to achieve the same degree of control and finesse that is known from the gas-phase quantum optics in the condensed phase. To do this, we combine concepts from quantum optics, laser spectroscopy, cryogenics, optical imaging, scanning probe technology and nanofluidics. In this endeavour, we have addressed a wide spectrum of scientific questions, ranging from quantum optics to biophysics. For more information, please consult our research website and our list of publications.

2002

Spontaneous emission of europium ions embedded in dielectric nanospheres

Hannes Schniepp, Vahid Sandoghdar

Physical Review Letters 89 257403 (2002) | Journal

We measure fluorescence lifetimes of emitters embedded in isolated single dielectric nanospheres. By varying the diameters of the spheres from 100 nm to 2 mum and by modifying their dielectric surrounding, we demonstrate a systematic change of paradigm in the spontaneous emission rate, as we cross the border from the superwavelength regime of Mie resonances to the nanoscopic realm of Rayleigh scattering. Our data show inhibition of the spontaneous emission up to 3 times and are in excellent agreement with the results of analytical calculations.

Nanometer resolution and coherent optical dipole coupling of two individual molecules

C. Hettich, C. Schmitt, J. Zitzmann, S. Kuhn, Ilja Gerhardt, Vahid Sandoghdar

Science 298 385-389 (2002) | Journal

By performing cryogenic laser spectroscopy under scanning probe electrode that induces local electric field, we have resolved two individual fluorescent molecules separated by 12 nanometers in an organic crystal. The two molecules undergo strong coherent dipole-dipole coupling that produces entangled sub- and superradiant states. Under intense laser illumination, both molecules are excited via two-photon transition, and the fluorescence from this doubly excited system displays photon bunching. Our experimental scheme can be used to optically resolve molecules at the nanometer scale and to manipulate the degree of entanglement among them.

Influence of a sharp fiber tip on high-Q modes of a microsphere resonator

Stephan Götzinger, O. Benson, Vahid Sandoghdar

Optics Letters 27 80-82 (2002) | Journal

We investigate the degradation of the Q factor of a fundamental whispering-gallery mode of a microsphere resonator when a fiber tip is placed in the evanescent field of the mode. With a tip diameter of 80 nm it is possible to maintain a Q factor exceeding 10(8), even when the tip is as close as 10 nm to the sphere surface. This result demonstrates the possibility of using such a tip as a "nanotool" to actively place a single nanoparticle in a single high-Q mode with great precision to achieve well-controlled coupling. (C) 2002 Optical Society of America.

Born on April 29, 1966 in Tehran, Iran. Bachelor of Science in Physics from the University of California in Davis (1987), Ph.D. in Physics (supervisors: E. A. Hinds and S. Haroche) from Yale University (1993), Postdoctoral Fellow at École Normale Supérieure (group of S. Haroche) in Paris. Head of the Nano-Optics group und habilitation in Physics at University of Konstanz (Chair of J. Mlynek). Professorship at Eidgenössischen Technischen Hochschule (ETH) Zurich (2001-2011). Recipient of an ERC Advanced Grant (2010). Alexander von Humboldt Professorship at Friedrich-Alexander-Universität Erlangen-Nürnberg and Director and Scientific Member at the Max Planck Institute for the Science of Light in Erlangen since 2011. Fellow of the Optical Society (OSA) and recepient of the 2023 Quantum Electronics and Optics Award for Fundamental Aspects from the European Physical Society. Founder of the Max-Planck-Zentrum für Physik und Medizin, a joint research center that aims to address questions in fundamental medical research with physical and mathematical methods.

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