Toru Yoshizawa

  • Citations Per Year
Learn More
Axially symmetric half-wave plates have been used to generate radially polarized beams that have constant phase in the plane transverse to propagation. However, since the retardance introduced by these waveplates depends on the wavelength, it is difficult to generate radially polarized beams achromatically. This paper describes a technique suitable for the(More)
An achromatic axially symmetric wave plate (AAS-WP) is proposed that is based on Fresnel reflections. The wave plate does not introduce spatial dispersion. It provides retardation in the wavelength domain with an axially symmetric azimuthal angle. The optical configuration, a numerical simulation, and the optical properties of the AAS-WP are described. It(More)
Vectorial vortex analysis is used to determine the polarization states of an arbitrarily polarized terahertz (0.1-1.6 THz) beam using THz achromatic axially symmetric wave (TAS) plates, which have a phase retardance of Δ = 163° and are made of polytetrafluorethylene. Polarized THz beams are converted into THz vectorial vortex beams with no spatial or(More)
In order to obtain an accurate Avogadro constant with a relative uncertainty of 1×10 to redefine the kilogram, the diameter of a perfect single crystal silicon sphere is required with the measurement uncertainty of 0.3 nm using the X-ray crystal density method. To achieve this, phase-shifting interferometers have been developed. A laser frequency tuning(More)
A projection moiré profilometry using a pair of liquid crystal digital gratings (LCDG) is applied to determine a step height using two liquid crystal digital gratings (LCDGs). Moiré contours are filtered over to remove the images of the original grating from the moiré counter when a pairs of grating images are traveled to the same direction in-phase(More)
  • 1