On-demand transfer of trapped photons on a chip

チップ上の微小点に保存した光の瞬時転送. 京都大学プレスリリース. 2016-05-26.Photonic crystal nanocavities, which have modal volumes of the order of a cubic wavelength in the material, are of great interest as flexible platforms for manipulating photons. Recent developments in ultra-high quality factor nanocavities with long photon lifetimes have encouraged us to develop an ultra-compact and flexible photon manipulation technology where photons are trapped in networks of such nanocavities. The most fundamental requirement is the on-demand transfer of photons to and from the trapped states of arbitrary nanocavities. We experimentally demonstrate photon transfer between two nearly resonant nanocavities at arbitrary positions on a chip, triggered by the irradiation of a third nonresonant nanocavity using an optical control pulse. We obtain a high transfer efficiency of ～90% with a photon lifetime of ～200 ps

Characteristics of the Potential Temperature Distribution Along Mountain Slopes Experiencing Cross-Mountain Air Currents in the Winter Season

In winter, northwesterly winds in the vicinity of Japan are predominant in the winter pressure distribution pattern that characterizes the climate of the environs of Japan, and on the Kanto Plain cross-mountain air currents frequently occur in winter because the winds pass over the Joshin’etsu mountainous region. A detailed analysis of the cross-mountain air currents is important to understanding the climate in the northwestern inland region of the Kanto Plain on the leeward side. In addition, little research has been conducted on the role of the gap flow in regard to the winter cross-mountain air currents. To address this shortage, advanced meteorological observation was carried out along the channel traversing the Joshin’etsu mountainous region, and that data was used to research the characteristics of the surface atmosphere along the mountain slopes when winter cross-mountain air currents blow. As a result, in the case in which cross-mountain air currents were not blowing, the potential temperature along the mountain slope tended to rise with altitude, in both the Sea of Japan side and Pacific Ocean side. However, in the case in which cross-mountain air currents were blowing, the potential temperature distribution was nearly uniform on the slope of the leeward, Pacific Ocean side, regardless of elevation. The case in which cross-mountain air currents were blowing had characteristics similar to foehn. This also suggests an impact by gap winds that pass through the Uonogawa-Tonegawa channel