Biomedical subjects

J Mlynek

Publications and source records attributed to J Mlynek.

At least 19 recordsLinked to original sources

PubMed2001

Tests of relativity using a cryogenic optical resonator.

A 190-day comparison of the optical frequencies defined by an optical cavity and a molecular electronic transition is analyzed for the velocity independence of the speed of light (Kennedy-Thorndike test) and the universality of the gravitational redshift. The modulation of the laboratory velocity and the gravitational potential were provided by Earth's orbital motion around the Sun. We find a velocity-dependence coefficient of (1.9+/-2.1)x10(-5), 3 times lower compared to the best previous test. Alternatively, the data confirm the gravitational redshift for an electronic transition at the 4% level. Prospects for significant improvements of the tests are discussed.

Journal Article↗

PubMed2001

Quantum state reconstruction of the single-photon Fock state.

We have reconstructed the quantum state of optical pulses containing single photons using the method of phase-randomized pulsed optical homodyne tomography. The single-photon Fock state 1> was prepared using conditional measurements on photon pairs born in the process of parametric down-conversion. A probability distribution of the phase-averaged electric field amplitudes with a strongly non-Gaussian shape is obtained with the total detection efficiency of (55+/-1)%. The angle-averaged Wigner function reconstructed from this distribution shows a strong dip reaching classically impossible negative values around the origin of the phase space.

Journal Article↗

PubMed2001

A single gold particle as a probe for apertureless scanning near-field optical microscopy.

We report on the fabrication, characterization and application of a probe consisting of a single gold nanoparticle for apertureless scanning near-field optical microscopy. Particles with diameters of 100 nm have been successfully and reproducibly mounted at the end of sharp glass fibre tips. We present the first optical images taken with such a probe. We have also recorded plasmon resonances of gold particles and discuss schemes for exploiting the wavelength dependence of their scattering cross-section for a novel form of apertureless scanning near-field optical microscopy.

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PubMed2000

Optical microscopy using a single-molecule light source

Rapid progress in science on nanoscopic scales has promoted increasing interest in techniques of ultrahigh-resolution optical microscopy. The diffraction limit can be surpassed by illuminating an object in the near field through a sub-wavelength aperture at the end of a sharp metallic probe. Proposed modifications of this technique involve replacing the physical aperture by a nanoscopic active light source. Advances in the spatial and spectral detection of individual fluorescent molecules, using near-field and far-field methods, suggest the possibility of using a single molecule as the illumination source. Here we present optical images taken with a single molecule as a point-like source of illumination, by combining fluorescence excitation spectroscopy with shear-force microscopy. Our single-molecule probe has potential for achieving molecular resolution in optical microscopy; it should also facilitate controlled studies of nanometre-scale phenomena (such as resonant energy transfer) with improved lateral and axial spatial resolution.

Journal Article↗

PubMed1999

Nanophase-separated polymer films as high-performance antireflection coatings

Optical surfaces coated with a thin layer to improve light transmission are ubiquitous in everyday optical applications as well as in industrial and scientific instruments. Discovered first in 1817 by Fraunhofer, the coating of lenses became standard practice in the 1930s. In spite of intensive research, broad-band antireflection coatings are still limited by the lack of materials with low refractive indices. A method based on the phase separation of a macromolecular liquid to generate nanoporous polymer films is demonstrated that creates surfaces with high optical transmission.

Journal Article↗

PubMed1996