Younghoon Song

One-step pipetting and assembly of encoded chemical-laden microparticles for high-throughput multiplexed bioassays

One quantitative liquid handling method in conventional assay processes is pipetting, which delivers a precise volume of one sample at a time. As this process becomes laborious and time-consuming as the number of samples increases, researchers in individual laboratories need a way to conduct large-scale assays in a reasonable amount of time and at an affordable cost. Here we report a novel handling technique of chemical substances termed partipetting, which allows the one-step pipetting of various chemical-laden hydrogels. We pipette and assemble various types of encoded chemical-laden microparticles in microwell arrays in parallel. The combination of this heterogeneous particle chip and a cell chip induces the release of the chemicals from the hydrogels and, eventually, the chemicals treat the targets. Based on bioassay applications using partipetting, we show its capability in large-scale bioassays, without the need for high-throughput bioassay resources, owing to a reduction in the assay costs and time.

Three-dimensional imaging of cavity vacuum with single atoms localized by a nanohole array

Zero-point electromagnetic fields were first introduced to explain the origin of atomic spontaneous emission. Vacuum fluctuations associated with the zero-point energy in cavities are now utilized in quantum devices such as single-photon sources, quantum memories, switches and network nodes. Here we present three-dimensional (3D) imaging of vacuum fluctuations in a high-Q cavity based on the measurement of position-dependent emission of single atoms. Atomic position localization is achieved by using a nanoscale atomic beam aperture scannable in front of the cavity mode. The 3D structure of the cavity vacuum is reconstructed from the cavity output. The root mean squared amplitude of the vacuum field at the antinode is also measured to be 0.92±0.07u2009Vu2009cm(-1). The present work utilizing a single atom as a probe for sub-wavelength imaging demonstrates the utility of nanometre-scale technology in cavity quantum electrodynamics.

Prescribed nondegenerate high-order modes in an axial-asymmetric high-finesse Fabry–Perot microcavity

We report an axial-asymmetric high-Q Fabry-Perot cavity supporting nondegenerate Hermite-Gaussian modes of the same mode order. Axial asymmetry of mirror surface was introduced by mechanically grinding off one side of a cylindrical mirror substrate without degrading the original mirror quality. The bases of the resulting Hermite-Gaussian modes were aligned with respect to the direction of grinding, making it possible to prescribe the mirror principal axes.

Atomic Solc filter: multi-resonant photoemission via periodic poling of atom-cavity coupling constant.

This paper describes a novel atom-cavity interaction induced by periodically poled atom-cavity coupling constant which leads to multiple narrow photoemission bands for an initially inverted two-level atom under the strong coupling condition. The emission bandpass narrowing has a close analogy with the folded Solc filter in the context of quasi-phase matching by periodic poling. We present a closed form solution of the emission probability at the end of interaction and deduce the multiple phase matching condition for this system which is programmable by the interaction time. The Bloch sphere analysis provides a clear understanding of the underlying atomic dynamics associated with the multiple resonances in the semiclassical limit. Furthermore, we show that this interaction can be applied to generation of nonclassical fields with sub-Poisson photon statistics.

Indirect measurement of three-photon correlation in nonclassical light sources

We have observed the three-photon correlation in nonclassical light sources by using an indirect measurement scheme based on the dead time effect of photon-counting detectors. We first developed a general theory which enables us to extract the three-photon correlation from the two-photon correlation of an arbitrary light source measured with detectors with finite dead times. We then confirmed the validity of our measurement scheme in experiments done with the cavity-QED microlaser operating with a large intra-cavity mean photon number exhibiting both sub- and super-poissoniaq photon statistics. The experimental results were in a good agreement with the theoretical expectation. Our measurement scheme provides an alternative approach for N-photon correlation measurement employing (N-1) detectors and thus a reduced measurement time for a given signal-to-noise ratio, compared to the usual scheme requiring N detectors.

Correction for the detector-dead-time effect on the second-order correlation of stationary sub-Poissonian light in a two-detector configuration

Exact measurement of the second-order correlation function

Liquid capped encoded microshell and partipetting for untraplex liquid assay

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Large scale structural color patterning using magnetochromatic microspheres with patterned magnet

of a light source is essential when investigating the photon statistics and the light generation process of the source. For a stationary single-mode light source, Mandel Q factor is directly related to

Optofluidic synthesis of magnetic microparticles with structural colors

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Spectrum Measurement Of The Cavity-QED Microlaser: Deviation From The Schawlow-Townes Linewidth

. For a large mean photon number in the mode, the deviation of