2026-01-15 量子科学技術研究機構
図1：極短パルス・軟X線発生の様子（左図）とそのスペクトル（右図、黒線）、および空気を透過させたスペクトル（右図、赤線）。窒素と酸素に固有な鋭い吸収が400 eVと540 eV近傍で同時に計測されました。
＜関連情報＞
- https://www.qst.go.jp/site/press/20260115.html
- https://opg.optica.org/ol/abstract.cfm?uri=ol-51-2-456
赤外光源を用いた軟X線高調波発生と酸素K吸収端におけるX線吸収端近傍構造の測定への応用 Soft x-ray high harmonic generation using an infrared light source and its application to the measurements of x-ray absorption near-edge structure at the oxygen K edge
Nobuhisa Ishii, Momoko Maruyama, and Ryuji Itakura
Optics Letters Published: January 14, 2026
DOI:https://doi.org/10.1364/OL.579282
Abstract
We demonstrate high harmonic generation beyond the water window using an intense infrared light source operating at 2000 nm in lithium niobate-based optical parametric chirped-pulse amplification by using an Yb:YAG thin-disk laser as a pump. The output pulses from the parametric amplifier (pulse energy: 1.68 mJ, wavelength: 1750–2500 nm, repetition rate: 5 kHz) are temporally compressed with an efficiency of 79% (1.32-mJ compressed pulse) down to 19.5 fs, which corresponds to the 2.9-cycle duration. The generated soft x-ray harmonics have been employed to measure x-ray absorption near-edge structure around the K edges of carbon, nitrogen, and oxygen, with acquisition times short enough to enable practical applications in time-resolved soft x-ray spectroscopy.
