Takeda M.,Utsunomiya University |
Takeda M.,University of Stuttgart
Optics Letters | Year: 2013
The spatial stationarity of scattered optical fields constitutes a basic premise of coherence holography and photon correlation holography. Nevertheless, spatial stationarity seems to have attracted less attention and still remains a less familiar concept than temporal stationarity because it has been a common practice in statistical optics to assume temporal ergodicity and replace the ensemble average with the time average, rather than the space average. To form the theoretical basis for coherence holography and photon correlation holography, an investigation is made into the spatial stationarity of the statistical optical field, and combinations of a light source and an optical system are identified that can create spatially stationary scattered fields. The result justifies the principles of coherence holography and photon correlation holography, and the previously reported experiments. © 2013 Optical Society of America.
Saitou Y.,Utsunomiya University |
Ishihara O.,Yokohama National University
Physical Review Letters | Year: 2013
The dynamic circulation of dust particles in a cylindrical complex plasma is studied experimentally. A levitated cloud of charged dust particles rotates around an axis in an ion flow induced by the coupling of applied magnetic field with the electric field due to plasma density gradient. The vertical and horizontal cross sections of the cloud reveal the dynamic circulation with helical trajectories of dust particles with meridional ascending motion near the axis. The dust particles in the center bottom in the cloud remain near a stagnation point and act like tea leaves in a teacup as described by Einstein in 1926. © 2013 American Physical Society.
Takeda M.,Utsunomiya University
Applied Optics | Year: 2013
The paper reviews a technique for fringe analysis referred to as Fourier fringe analysis (FFA) or the Fourier transform method, with a particular focus on its application to metrology of extreme physical phenomena. Examples include the measurement of extremely small magnetic fields with subfluxon sensitivity by electron wave interferometry, subnanometer wavefront evaluation of projection optics for extreme UV lithography, the detection of sub-Ångstrom distortion of a crystal lattice, and the measurement of ultrashort optical pulses in the femotsecond to attosecond range, which show how the advantages of FFA are exploited in these cutting edge applications. © 2012 Optical Society of America.
Kodama Y.,Utsunomiya University |
Hu C.-D.,Purdue University
BioTechniques | Year: 2012
Over the past decade, bimolecular fluorescence complementation (BiFC) has emerged as a key technique to visualize protein-protein interactions in a variety of model organisms. The BiFC assay is based on reconstitution of an intact fluorescent protein when two complementary non-fluorescent fragments are brought together by a pair of interacting proteins. While the originally reported BiFC method has enabled the study of many protein-protein interactions, increasing demands to visualize protein-protein interactions under various physiological conditions have not only prompted a series of recent BiFC technology improvements, but also stimulated interest in developing completely new approaches. Here we review current BiFC technology, focusing on the development and improvement of BiFC systems, the understanding of split sites in fluorescent proteins, and enhancements in the signal-to-noise ratio. In addition, we provide perspectives on possible future improvements of the technique.
Uehara N.,Utsunomiya University
Analytical Sciences | Year: 2010
In this brief review, gold nanoparticles conjugated with functional polymers are described from the viewpoint of application to sensing materials. The optical properties of gold nanoparticles, the synthesis of polymer-functionalized gold nanoparticles, and their analytical applications are discussed. Polymer-functionalized gold nanoparticles are categorized into two classes: biopolymer-conjugated gold nanoparticles and artificial-polymer conjugated gold nanoparticles. Fluorometric and colorimetric sensing using gold nanoparticles are focused; fluorometric detection enables us to exploit sensitive assays for practical use. Furthermore, chemical amplification using gold nanoparticles is also discussed for the sensitive probing. © 2010 The Japan Society for Analytical Chemistry.