2026-09-04 千葉大学
図：シャドウ効果画像から位相画像への再構成
＜関連情報＞
- https://www.chiba-u.jp/news/research-collab/post_713.html
- https://opg.optica.org/oe/fulltext.cfm?uri=oe-34-18-34443
らせん位相フィルタリングと単一ピクセル検出によるテラヘルツ位相感応イメージング Terahertz phase-sensitive imaging via spiral-phase filtering and single-pixel detection
Shusaku Mikami, Yusuke Odagiri, Wataru Sennzaki, Adam Vallés, Seigo Ohno, and Katsuhiko Miyamoto
Optics Express Published: September 2, 2026
DOI:https://doi.org/10.1364/OE.610381
Abstract
We present a robust phase-sensitive imaging approach for the terahertz (THz) region based on spiral-phase filtering combined with single-pixel imaging (SPI). By introducing a spiral phase plate at the Fourier plane of a 4f optical system, spatial phase variations are converted into measurable intensity distributions through the shadow effect. Unlike conventional THz techniques that rely on interferometric or time-domain detection, the proposed approach operates in a monochromatic, common-path configuration, enabling compact and alignment-insensitive implementation. The method is intrinsically sensitive to spatial phase gradients and discontinuities, as uniform phase regions are suppressed while phase variations are converted into measurable intensity patterns through spiral-phase filtering. Experiments demonstrate characteristic phase-dependent responses, including orbital angular momentum (OAM)-dependent intensity inversion, initial-phase-controlled rotation of intensity patterns, multi-vortex generation, and phase inversion in structured objects. Furthermore, spatial phase information can be retrieved from intensity-only measurements using a phase-modulation-based reconstruction approach. These results establish spiral-phase filtering as a practical platform for phase-gradient-sensitive imaging in the THz region and highlight its potential for compact and versatile phase-sensitive THz imaging using monochromatic radiation.
