Fresnel lens optical fiber tweezers to evaluate the vitality of single algae cells.

Dunaliella salina algae are trapped and studied using dual-fiber optical tweezers based on nano-imprinted Fresnel lenses. Different forms of cyclic motion of living algae inside the optical trap are observed and analyzed. A characteristic periodic motion in the 0-35 Hz frequency region reflects the algal flagella activity and is used to estimate the algal vitality, by photomovement.

Excitation of whispering gallery modes with a "point-and-play," fiber-based, optical nano-antenna.

We demonstrate the excitation and detection of whispering gallery modes in optical microresonators using a "point-and-play," fiber-based, optical nano-antenna. The coupling mechanism is based on cavity-enhanced Rayleigh scattering. Collected spectra exhibit Lorentzian dips, Fano shapes, or Lorentzian peaks, with a coupling efficiency around 13%.

Out-of-equilibrium force measurements of dual-fiber optical tweezers.

Optical trapping of micron-size dielectric particles in a dual-fiber tip configuration is presented. Trap oscillation and suspension flow experiments are performed to investigate the linearity of the optical forces. These measurements are completed by standard methods such as Boltzmann statistics or power spectra evaluation.

Luminescent nanoparticle trapping with far-field optical fiber-tip tweezers.

We report stable and reproducible trapping of luminescent dielectric YAG:Ce(3+) nanoparticles with sizes down to 60 nm using far-field dual fiber tip optical tweezers. The particles are synthesized by a specific glycothermal route followed by an original protected annealing step, resulting in significantly enhanced photostability. The tweezers properties are analyzed by studying the trapped particles residual Brownian motion using video or reflected signal records.

Single and dual fiber nano-tip optical tweezers: trapping and analysis.

An original optical tweezers using one or two chemically etched fiber nano-tips is developed. We demonstrate optical trapping of 1 micrometer polystyrene spheres at optical powers down to 2 mW. Harmonic trap potentials were found in the case of dual fiber tweezers by analyzing the trapped particle position fluctuations.

Transmission and reflection characteristics of metal-coated optical fiber tip pairs.

The optical transmission and reflection in between two metalized optical fiber tips is studied in the optical near-field and far-field domains. In addition to aluminum-coated tips for near-field scanning optical microscopy (NSOM), specifically developed gold-coated fiber tips cut by focused ion beam are investigated. Transverse transmission maps of subwavelength width clearly indicate optical near-field coupling between the tips for short tip distances and become essentially Gaussian-shaped for larger distances in the far-field regime.

Living cell imaging by far-field fibered interference scanning optical microscopy.

We report on the imaging of biological cells including living neurons by a dedicated fibered interferometric scanning optical microscope. The topography and surface roughness of mouse fibroblasts and hippocampal neurons are clearly revealed. This straightforward far-field technique allows fast, high resolution observation of samples in liquids without lengthy alignment procedures or costly components.

Surface plasmon-mediated far-field emission of laser dye solutions.

Angle-resolved reflection and emission spectra of metal gratings consisting of subwavelength grooves and immersed into rhodamine B and rhodamine 19 solutions are presented. The measured reflection and emission dispersion diagrams reveal the surface plasmon polaritons positions and strong plasmon-mediated emission enhancement, respectively. The same grating could be easily reused for the characterization of different dye molecules.

Y0.9 Er0.1 Al3(BO3)4 thin films prepared by the polymeric precursor method for integrated optics.

This work reports on the optimization of Yo.9 Er0.1 Al3(BO3)4 thin films for integrated optics.