We investigate a nonlinear localization microscopy method based on Rabi oscillations of single emitters. We demonstrate the fundamental working principle of this technique using a cryogenic far-field experiment in which subwavelength features smaller than lambda/10 are obtained. Using Monte Carlo simulations, we show the superior localization accuracy of this method under realistic conditions and a potential for higher acquisition speed or a lower number of required photons as compared to conventional linear schemes. The method can be adapted to other emitters than molecules and allows for the localization of several emitters at different distances to a single measurement pixel.
Near-infrared single-photons from aligned molecules in ultrathin crystalline films at room temperature
C. Toninelli,
K. Early,
J. Bremi,
A. Renn,
Stephan Götzinger,
Vahid Sandoghdar
We investigate the optical properties of Dibenzoterrylene (DBT) molecules in a spin-coated crystalline film of anthracence. By performing single molecule studies, we show that the dipole moments of the DBT molecules are oriented parallel to the plane of the film. Despite a film thickness of only 20 nm, we observe an exceptional photostability at room temperature and photon count rates around 10 6 per second from a single molecule. These properties together with an emission wavelength around 800 nm make this system attractive for applications in nanophotonics and quantum optics. (C) 2010 Optical Society of America
Spontaneous emission of a nanoscopic emitter in a strongly scattering disordered medium
P. V. Ruijgrok,
R. Wuest,
A. A. Rebane,
A. Renn,
Vahid Sandoghdar
Fluorescence lifetimes of nitrogen-vacancy color centers in individual diamond nanocrystals were measured at the interface between a glass substrate and a strongly scattering medium. Comparison of the results with values recorded from the same nanocrystals at the glass-air interface revealed fluctuations of fluorescence lifetimes in the scattering medium. After discussing a range of possible systematic effects, we attribute the observed lengthening of the lifetimes to the reduction of the local density of states. Our approach is very promising for exploring the strong three-dimensional localization of light directly on the microscopic scale. (C) 2010 Optical Society of America
Quantum Interference of Tunably Indistinguishable Photons from Remote Organic Molecules
R. Lettow,
Y. L. A. Rezus,
A. Renn,
G. Zumofen,
E. Ikonen,
Stephan Götzinger,
Vahid Sandoghdar
We demonstrate two-photon interference using two remote single molecules as bright solid-state sources of indistinguishable photons. By varying the transition frequency and spectral width of one molecule, we tune and explore the effect of photon distinguishability. We discuss future improvements on the brightness of single-photon beams, their integration by large numbers on chips, and the extension of our experimental scheme to coupling and entanglement of distant molecules.
Fluorescence Enhancement with the Optical (Bi-) Conical Antenna
Ahmad Mohammadi,
Franziska Kaminski,
Vahid Sandoghdar,
Mario Agio
The Journal of Physical Chemistry C
114
7372-7377
(2010)
| Journal
We investigate the properties of finite gold nanocones as optical antennas for enhancing molecular fluorescence. We compute the modification of the excitation rate, spontaneous emission rate, and quantum efficiency as a function of the nanocone base and length, showing that the maximum field and fluorescence enhancements do not occur for the same nanocone parameters. We compare the results with those for nanorods and nanospheroids and find that nanocones perform better.
Single-Molecule Sensitivity in Optical Absorption at Room Temperature
Philipp Kukura,
Michele Celebrano,
Alois Renn,
Vahid Sandoghdar
The Journal of Physical Chemistry Letters
1
3323-3327
(2010)
| Journal
Sensitive detection of condensed matter is of utmost importance in fundamental research as well as cutting-edge applications such as molecular analytics and diagnostics. Until very recently, all existing methods for the detection of single molecules at room temperature have required highly efficient fluorophores. Here we demonstrate, for the first time that single molecules can also be detected via standard modulation-free absorption measurements. Our work extends single-molecule detection to a huge class of materials that absorb light but do not fluoresce efficiently.
Geometry-induced electrostatic trapping of nanometric objects in a fluid
Madhavi Krishnan,
Nassiredin Mojarad,
Philipp Kukura,
Vahid Sandoghdar
The ability to trap an object-whether a single atom or a macroscopic entity-affects fields as diverse as quantum optics(1), soft condensed-matter physics, biophysics and clinical medicine(2). Many sophisticated methodologies have been developed to counter the randomizing effect of Brownian motion in solution(3-10), but stable trapping of nanometre-sized objects remains challenging(8-10). Optical tweezers are widely used traps, but require sufficiently polarizable objects and thus are unable to manipulate small macromolecules. Confinement of single molecules has been achieved using electrokinetic feedback guided by tracking of a fluorescent label, but photophysical constraints limit the trap stiffness and lifetime(8). Here we show that a fluidic slit with appropriately tailored topography has a spatially modulated electrostatic potential that can trap and levitate charged objects in solution for up to several hours. We illustrate this principle with gold particles, polymer beads and lipid vesicles with diameters of tens of nanometres, which are all trapped without external intervention and independently of their mass and dielectric function. The stiffness and stability of our electrostatic trap is easily tuned by adjusting the system geometry and the ionic strength of the solution, and it lends itself to integration with other manipulation mechanisms. We anticipate that these features will allow its use for contact-free confinement of single proteins and macromolecules, and the sorting and fractionation of nanometre-sized objects or their assembly into high-density arrays.
Nanofocusing radially-polarized beams for high-throughput funneling of optical energy to the near field
We theoretically show that a weakly-focused radially polarized beam can excite surface-plasmon-polaritons in metal nanowires and nanocones with efficiencies of the order of 90% and large bandwidths. The coupling mechanism relies on the formation of a standing wave on the nanowire facet, which imposes a relationship between the operating wavelength and the nanowire radius. An immediate application of this finding is nanofocusing of optical energy for implementations of ultra-fast and high-throughput linear and nonlinear nanoscopies, optical nanolithographies, quantum nano-optics and photochemistry at the nanoscale. (C)2010 Optical Society of America
Efficient coupling of single photons to single plasmons
M. Celebrano,
R. Lettow,
P. Kukura,
M. Agio,
A. Renn,
Stephan Götzinger,
Vahid Sandoghdar
We demonstrate strong coupling of single photons emitted by individual molecules at cryogenic and ambient conditions to individual nanoparticles. We provide images obtained both in transmission and reflection, where an efficiency greater than 55% was achieved in converting incident narrow-band photons to plasmon-polaritons (plasmons) of a silver nanoparticle. Our work paves the way to spectroscopy and microscopy of nano-objects with sub-shot noise beams of light and to triggered generation of single plasmons and electrons in a well-controlled manner. (C) 2010 Optical Society of America
A scanning microcavity for in situ control of single-molecule emission
C. Toninelli,
Y. Delley,
T. Stoeferle,
A. Renn,
Stephan Götzinger,
Vahid Sandoghdar
We report on the fabrication and characterization of a scannable Fabry-Perot microcavity, consisting of a curved micromirror at the end of an optical fiber and a planar distributed Bragg reflector. Furthermore, we demonstrate the coupling of single organic molecules embedded in a thin film to well-defined resonator modes. We discuss the choice of cavity parameters that will allow sufficiently high Purcell factors for enhancing the zero-phonon transition between the vibrational ground levels of the electronic excited and ground states. (C) 2010 American Institute of Physics. [doi:10.1063/1.3456559]
Contact
Nano-Optics Division Prof. Vahid Sandoghdar
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
