偏光光のねじれを完全に捉える新技術を開発(New technique captures every twist of polarized light)

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2025-07-02 スイス連邦工科大学ローザンヌ校(EPFL)

スイス連邦工科大学ローザンヌ校(EPFL)の研究チームは、光の偏光状態(直線・円偏光)を高感度かつ広帯域・時間分解で観測できる新技術を開発した。この手法は、「ストークスベクトル」と呼ばれる光の全偏光情報を400~900nmの広い波長域、ナノ秒~ミリ秒の時間スケールで検出可能で、従来法では難しかった微弱な信号も感度1万分の1で捕捉できる。従来技術では速度・感度・波長範囲のいずれかを犠牲にする必要があったが、本技術は全てを両立。市販部品で構成され、光学設計図や自動化アルゴリズムも公開されており、再現性と普及性が高い。未知の有機発光体の偏光挙動や誤信号(アーチファクト)も識別可能で、量子材料・ホログラム・偏光ディスプレイなどへの応用が期待される。

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広帯域過渡フルストークスルミネッセンス分光法 Broadband transient full-Stokes luminescence spectroscopy

Antti-Pekka M. Reponen,Marcel Mattes,Zachary A. VanOrman,Lilian Estaque,Grégory Pieters & Sascha Feldmann
Nature  Published:25 June 2025
DOI:https://doi.org/10.1038/s41586-025-09197-3

Abstract

Materials emitting circularly polarized light (CPL) are highly sought after for applications ranging from efficient displays to quantum information technologies1,2,3,4,5,6,7. However, established methods for time-resolved CPL (TRCPL) characterization have notable limitations8,9,10,11,12,13,14,15,16,17, generally requiring a compromise between sensitivity, accessible timescales and spectral information. This has limited the acquisition of in-depth photophysical insight necessary for materials development. Here we demonstrate a high-sensitivity (noise level of the order of 10−4), broadband (about 400–900 nm), transient (nanosecond resolution, millisecond range) full-Stokes (CPL and linear polarizations) spectroscopy setup. The achieved combination of high-sensitivity, broad wavelength response and flexible time ranges represents a substantial advancement over previous TRCPL approaches. As a result, TRCPL measurements are shown to be applicable to hitherto inaccessible material systems and photophysical processes, including systems with low (10−3) dissymmetry factors and luminescence pathways spanning nanosecond to millisecond time ranges. Finally, full-Stokes measurements allow tracking the temporal evolution of linear polarization components, of interest by themselves, but especially relevant in the context of controlling for associated CPL artefacts18,19 in the time domain.

1700応用理学一般
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