Yoshihiko Inoue

Cylindrical Vector Laser Beam Generated by the Use of a Photonic Crystal Mirror

A concentrically patterned photonic crystal mirror with polarization selectivity fabricated by the autocloning technique was used for the generation of radially and azimuthally polarized beams from an Nd:YAG laser cavity. By adopting the photonic crystal mirror as the output coupler of the cavity, both radially and azimuthally polarized beams were obtained with similar output power as that of an unpolarized beam generated by a conventional, non-polarization-selective output coupler.

Multichannel Photonic Crystal Wavelength Filter Array for Near-Infrared Wavelengths

Multichannel wavelength filters consisting of 2-D photonic crystal (PhC) for the near-infrared wavelength region (~800 nm) are demonstrated. The filter is a thin-film wavy multilayer structure and is fabricated by the autocloning method, which is based on a radio frequency bias sputtering process. Twelve long-pass-type filter regions are integrated on a common silica substrate. Sharp cutoff characteristics and almost equal channel spacing are experimentally verified. To precisely control the effective lattice constant of PhC, a modulated lattice structure on the substrate is utilized

Sharp edge wavelength filters utilizing multilayer photonic crystals

A novel configuration of dielectric multilayer wavelength filters for enabling sharp cut-off characteristics is proposed. By applying perturbations to the multilayer structures such as corrugation or lateral film isolation, deep optical stopbands can be created as a result of the coupling between the obliquely and horizontally propagating light waves. Numerical simulation by FDTD revealed that the proposed structure had approximately two to three times larger decay constants than that of unmodulated flat multilayer.

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. We also talk about deducing a samples three-dimensional shape for a reflection-type microscope. The efficiency of the method is demonstrated experimentally.