Susumu Noda

An artificial crystal structure has been fabricated exhibiting a full three-dimensional photonic bandgap effect at optical communication wavelengths. The photonic crystal was constructed by stacking 0.7-micrometer period semiconductor stripes with the accuracy of 30 nanometers by advanced wafer-fusion technique. A bandgap effect of more than 40 decibels (which corresponds to 99.99% reflection) was successfully achieved. The result encourages us to create an ultra-small optical integrated circuit

We demonstrate polarization mode selection in a two-dimensional (2D) photonic crystal laser by controlling the geometry of the unit cell structure. As the band diagram of the square-lattice photonic crystal is influenced by the unit cell structure, calculations reveal that changing the structure from a circular to an elliptical geometry should result in a strong modification of the electromagnetic field distributions at the band edges. Such a structural modification is expected to provide a mech

Three-dimensional (3D) photonic crystals containing artificial point defects have been fabricated to emit light at optical communications wavelengths. They were constructed by stacking 0.7-micrometer-period gallium arsenide striped layers, resulting in a 3D "woodpile" photonic crystal. Indium-gallium arsenide-phosphide quantum-well layers emitting at a wavelength of 1.55 micrometers were incorporated in the center of the crystal. Samples having up to nine stacked layers were constructed, and art

Shorter-wavelength surface-emitting laser sources are important for a variety of fields, including photonics, information processing, and biology. We report on the creation of a current-driven blue-violet photonic-crystal surface-emitting laser. We have developed a fabrication method, named "air holes retained over growth," in order to construct a two-dimensional gallium nitride (GaN)/air photonic-crystal structure. The resulting periodic structure has a photonic-crystal band-edge effect suffici

Photonic crystals (PCs) are optical materials of periodic refractive index, designed to block light of certain wavelengths ( [1][1] – [5][2] ). Artificial defects such as line- and/or point-defects can be introduced into PCs to allow light to be manipulated. Ultrasmall photonic devices, with sizes

Deep reinforcement learning empowers automated inverse design and optimization of photonic crystals for nanoscale laser cavities,

Photonic-crystal surface-emitting lasers (PCSELs) have attracted much attention for their unrivaled capabilities, such as broad area, coherent resonance, tailored beam patterns, and beam steering. In this paper, we first review the progress of PCSELs, then introduce a novel concept of modulated photonic-crystal surface-emitting lasers (M-PCSELs) for realizing both lasing oscillation and on demand, beam diffraction for any two-dimensional direction in free space without the need for external elem

Photonic crystal (PC) nanocavities have been receiving a great deal of attention recently because of their ability to strongly confine photons in a tiny space with a high quality factor. According to cavity quantum electrodynamics (cavity QED), such confined photons can achieve efficient interactions with excitons in semiconductors, leading to the Purcell effect in the weak coupling regime and vacuum Rabi splitting (VRS) in the strong coupling regime. These features are promising for application

A new realization method for three-dimensional photonic crystals in the optical wavelength region is proposed. Microfabrication techniques using wafer-bonding, selective etching, and laser beam deflection pattern observation techniques are successfully combined, and the feasibility of the proposed method is experimentally demonstrated.