Simultaneous imaging of multiple cellular events using high-accuracy fluorescence polarization microscopy.

Förster resonance energy transfer (FRET) has been widely used to design indicators for biomolecules. Conventional FRET-based indicators enable quantitative measurements of analyzes by calculating the ratio between donor and acceptor fluorophores. However, such 'hetero-FRET'-based indicators, which use multiple differently colored fluorophores, restrict the simultaneous use of other colors of fluorescent molecules.

Multi-level signaling in the Stokes space and its application to large-capacity optical communications.

The Stokes vector of an optical signal does not depend on its absolute phase; therefore, we can construct the phase-insensitive optical communication system, using the Stokes vector as a modulation parameter. In such a system, multi-level optical signals can effectively be designed in the three-dimensional Stokes space and demodulated either by direct detection or by coherent detection, where low-complexity digital-signal processing (DSP) is employed. Although this system has the disadvantage that adaptive equalizers can hardly be implemented in the digital domain, it is still an attractive solution to large-capacity (≥ 100 Gbit/s) and medium-or short-reach (≤ 100 km) transmission.

Differential interference contrast microscope using photonic crystals for phase imaging and three-dimensional shape reconstruction.

We present a differential interference contrast microscope using photonic crystals capable of real-time capture of both phase and amplitude components independently without moving parts. Unlike previous methods using rotating polarizers to discriminate each component, we propose using a special camera equipped with an arrayed polarizer whose instant polarization measurement allows real-time acquisition of the phase gradient information. A two-image algorithm is used to reconstruct the phase two-dimensional distribution of biological samples from the gradient information with a transmission-type microscope.

Simultaneous generation of helical beams with linear and radial polarization by use of a segmented half-wave plate.

Simultaneous generation of helical beams with linear and radial polarization is demonstrated by use of a segmented half-wave plate in a Ti:sapphire laser cavity. A linearly polarized Laguerre-Gaussian beam is converted to a radially polarized beam with a spiral phase shift and vice versa. In addition, these two beams coexist in the cavity, and the cavity emits one of these two beams from an output coupler.

Compact ellipsometer employing a static polarimeter module with arrayed polarizer and wave-plate elements.

A portable ellipsometer with a compact static polarimeter using an arrayed polarizer, an arrayed wave plate, and a CCD image sensor is developed. A high level of repeatability at a measurement speed of 0.3 s is demonstrated by measurement of SiO(2) films ranging from 2 to 300 nm in thickness deposited on an Si wafer.