Near-infrared spectroscopy

  • Article
    | Open Access

    Here, the authors use a nanoscale probe to study the photoresponse within a single moiré unit cell of minimally twisted bilayer graphene, and observe an intricate photo-thermoelectric response attributed to the Seebeck coefficient variation at AB-BA domain boundaries.

    • Niels C. H. Hesp
    • , Iacopo Torre
    •  & Frank H. L. Koppens
  • Article
    | Open Access

    Quantifying lipid and water content in tissues non-invasively is difficult, and no method exists to quantify lipids in blood non-invasively. Here the authors develop an imaging approach called shortwave infrared meso-patterned imaging (SWIR-MPI) to detect and spatially map tissue water and lipids in preclinical models.

    • Yanyu Zhao
    • , Anahita Pilvar
    •  & Darren Roblyer
  • Article
    | Open Access

    Efficient generation of phonons is an important ingredient for a prospective electrically-driven phonon laser for coherent control of quantum systems. Here, the authors report on laser-like phonon emission in a hybrid semiconductor microcavity that optomechanically couples BEC polaritons with phonons.

    • D. L. Chafatinos
    • , A. S. Kuznetsov
    •  & A. Fainstein
  • Article
    | Open Access

    The synthesis of hydrocarbons with attractive electronic structures remains challenging. Here, the authors describe the synthesis and properties of the C70 fragment as-indaceno[3,2,1,8,7,6-ghijklm]terrylene, which exhibits near-infrared (NIR) absorption.

    • Yuki Tanaka
    • , Norihito Fukui
    •  & Hiroshi Shinokubo
  • Article
    | Open Access

    Typically, the performance of the state-of-the-art laser sensors is insufficient for many high precision applications. Here, the authors report mode-phase-difference photothermal spectroscopy with a dual-mode anti-resonant hollow-core optical fiber and demonstrate acetylene detection with ultra-high sensitivity.

    • Pengcheng Zhao
    • , Yan Zhao
    •  & Pu Wang
  • Article
    | Open Access

    Diffuse optical flowmetry is widely used to assess blood flow dynamics, but has remained difficult to interpret. Here, the authors use interferometric near-infrared spectroscopy, revealing additional information about optical phase and time-of-flight, and observe the Brownian nature of blood flow dynamics in humans.

    • Oybek Kholiqov
    • , Wenjun Zhou
    •  & Vivek J. Srinivasan
  • Article
    | Open Access

    Chemical defects endow materials with unique properties but their investigation is challenging due to their small footprint. Here the authors develop a high throughput shortwave infrared spectroscopy method enabling spectral identification and quantitative counting of fluorescent chemical defects at the single defect level.

    • Xiaojian Wu
    • , Mijin Kim
    •  & YuHuang Wang
  • Article
    | Open Access

    The unique valley and spin texture of atomically thin transition metal dichalcogenides (TMDs) allows the observation of the valley Zeeman effect for neutral and charged excitons. Here, the authors unveil the underlying physics of the magneto-optical response and valley Zeeman splitting of trions in tungsten-based TMDs.

    • T. P. Lyons
    • , S. Dufferwiel
    •  & A. I. Tartakovskii
  • Article
    | Open Access

    Dual-comb interferometry promises to be a high-precision metrology technique, but is hindered by short coherence times that limit the maximum number of averages. Here, Chen et al. achieve mutual coherence times of almost 2000 s by feed-forward stabilization of the carrier-envelope offsets.

    • Zaijun Chen
    • , Ming Yan
    •  & Nathalie Picqué
  • Article
    | Open Access

    Fano lineshapes are found in many photonic systems where discrete and extended spectra interfere. Here, the authors extend this description and introduce generalized Fano lineshapes to describe the results from hyperspectral mapping around an exceptional point in a coupled-cavity system.

    • Niccolò Caselli
    • , Francesca Intonti
    •  & Massimo Gurioli
  • Article
    | Open Access

    Spectroscopic ellipsometry is an established technique to characterize the optical properties of a material. Here, Minamikawa et al. combine the method with dual-comb spectroscopy, which allows them to obtain ellipsometric parameters including the phase difference between s-polarized and p-polarized light.

    • Takeo Minamikawa
    • , Yi-Da Hsieh
    •  & Takeshi Yasui
  • Article
    | Open Access

    Atomically thin transition metal dichalcogenides host excitons and trions, however higher-order states, although possible, are difficult to identify experimentally. Here, the authors perform polarization-resolved coherent spectroscopy to unveil the signature of neutral and charged inter-valley biexcitons in monolayer MoSe2.

    • Kai Hao
    • , Judith F. Specht
    •  & Galan Moody
  • Article
    | Open Access

    Functional imaging of proteolytic activity is an emerging strategy to guide patient diagnosis and monitor clinical outcome. Here the authors present a peptide-based probe to detect and localize thrombin activity ex vivoand non-invasively in mouse models of wounding and pulmonary thrombosis.

    • Michael J. Page
    • , André L. Lourenço
    •  & Charles S. Craik