scholarly journals Excited States Engineering Enables Efficient Near-Infrared Lasing in Nanographenes

2021 ◽  
Author(s):  
Giuseppe Maria Paternò ◽  
Qiang Chen ◽  
Rafael Muñoz-Mármol ◽  
Michele Guizzardi ◽  
Victor Bonal Díaz ◽  
...  
Keyword(s):  
Excited States ◽  
Near Infrared ◽  
Stimulated Emission ◽  
Spectral Overlap ◽  
Gain Loss

The spectral overlap between stimulated emission (SE) and absorption from dark states (i.e. charges and triplets) especially in the near-infrared (NIR), represents one of the most effective gain loss channel...

scholarly journals Optimization of Advanced Live-Cell Imaging through Red/Near-Infrared Dye Labeling and Fluorescence Lifetime-Based Strategies

2021 ◽  
Vol 22 (20) ◽  
pp. 11092
Author(s):  
Magalie Bénard ◽  
Damien Schapman ◽  
Christophe Chamot ◽  
Fatéméh Dubois ◽  
Guénaëlle Levallet ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Live Cell Imaging ◽  
Near Infrared ◽  
Cell Imaging ◽  
Light Exposure ◽  
Photon Counting ◽  
Live Cell ◽  
Stimulated Emission ◽  
Plot Analysis ◽  
Phasor Plot

Fluorescence microscopy is essential for a detailed understanding of cellular processes; however, live-cell preservation during imaging is a matter of debate. In this study, we proposed a guide to optimize advanced light microscopy approaches by reducing light exposure through fluorescence lifetime (τ) exploitation of red/near-infrared dyes. Firstly, we characterized key instrumental elements which revealed that red/near-infrared laser lines with an 86x (Numerical Aperture (NA) = 1.2, water immersion) objective allowed high transmission of fluorescence signals, low irradiance and super-resolution. As a combination of two technologies, i.e., vacuum tubes (e.g., photomultiplier) and semiconductor microelectronics (e.g., avalanche photodiode), type S, X and R of hybrid detectors (HyD-S, HyD-X and HyD-R) were particularly adapted for red/near-infrared photon counting and τ separation. Secondly, we tested and compared lifetime-based imaging including coarse τ separation for confocal microscopy, fitting and phasor plot analysis for fluorescence lifetime microscopy (FLIM), and lifetimes weighting for enhanced stimulated emission depletion (STED) nanoscopy, in light of red/near-infrared multiplexing. Mainly, we showed that the choice of appropriate imaging approach may depend on fluorochrome number, together with their spectral/lifetime characteristics and STED compatibility. Photon-counting mode and sensitivity of HyDs together with phasor plot analysis of fluorescence lifetimes enabled the flexible and fast imaging of multi-labeled living H28 cells. Therefore, a combination of red/near-infrared dyes labeling with lifetime-based strategies offers new perspectives for live-cell imaging by enhancing sample preservation through acquisition time and light exposure reduction.

Multiphonon Relaxation of Near-Infrared Excited States of LaCl3:Dy3+

1967 ◽  
Vol 159 (2) ◽  
pp. 262-266 ◽  
Author(s):  
L. A. Riseberg ◽  
W. B. Gandrud ◽  
H. W. Moos
Keyword(s):  
Excited States ◽  
Near Infrared ◽  
Multiphonon Relaxation

scholarly journals Multidimensional spectroscopy with attosecond extreme ultraviolet and shaped near-infrared pulses

2018 ◽  
Vol 4 (9) ◽  
pp. eaau3783 ◽  
Author(s):  
Hugo J. B. Marroux ◽  
Ashley P. Fidler ◽  
Daniel M. Neumark ◽  
Stephen R. Leone
Keyword(s):  
Excited States ◽  
Near Infrared ◽  
Extreme Ultraviolet ◽  
Four Wave Mixing ◽  
High Dimensionality ◽  
Wave Mixing ◽  
Multidimensional Spectroscopy ◽  
Electronic Dynamics ◽  
Single State ◽  
Signal Field

Dynamics following excitation with attosecond extreme ultraviolet (XUV) pulses arise from enormous numbers of accessible excited states, complicating the retrieval of state-specific time evolutions. We develop attosecond XUV multidimensional spectroscopy here to separate interfering pathways on a near-infrared (NIR) energy axis, retrieving single state dynamics in argon atoms in a two-dimensional (2D) XUV-NIR spectrum. In this experiment, we measure four-wave mixing signal arising from the interaction of XUV attosecond pulses centered around 15 eV with two few-cycle NIR pulses. The 2D spectrum is created by measuring the emitted XUV signal field spectrum while applying narrowband amplitude and phase modulations to one of the NIR pulses. Application of such a technique to systems of high dimensionality will provide for the observation of state-resolved pure electronic dynamics, in direct analogy to phenomena unraveled by multidimensional spectroscopies at optical frequencies.

scholarly journals An Operational Workflow of Deciduous-Dominated Forest Species Classification: Crown Delineation, Gap Elimination, and Object-Based Classification

2019 ◽  
Vol 11 (18) ◽  
pp. 2078 ◽  
Author(s):  
Yuhong He ◽  
Jian Yang ◽  
John Caspersen ◽  
Trevor Jones
Keyword(s):  
Tree Species ◽  
Near Infrared ◽  
Deciduous Forest ◽  
Structural Diversity ◽  
Species Classification ◽  
Individual Tree ◽  
Spectral Overlap ◽  
Object Based ◽  
Early Fall ◽  
Crown Delineation

Recent advances in remote sensing technology provide sufficient spatial detail to achieve species-level classification over large vegetative ecosystems. In deciduous-dominated forests, however, as tree species diversity and forest structural diversity increase, the frequency of spectral overlap between species also increases and our ability to classify tree species significantly decreases. This study proposes an operational workflow of individual tree-based species classification for a temperate, mixed deciduous forest using three-seasonal WorldView images, involving three steps of individual tree crown (ITC) delineation, non-forest gap elimination, and object-based classification. The process of species classification started with ITC delineation using the spectral angle segmentation algorithm, followed by object-based random forest classifications. A total of 672 trees was located along three triangular transects for training and validation. For single-season images, the late-spring, mid-summer, and early-fall images achieve the overall accuracies of 0.46, 0.42, and 0.35, respectively. Combining the spectral information of the early-spring, mid-summer, and early-fall images increases the overall accuracy of classification to 0.79. However, further adding the late-fall image to separate deciduous and coniferous trees as an extra step was not successful. Compared to traditional four-band (Blue, Green, Red, Near-Infrared) images, the four additional bands of WorldView images (i.e., Coastal, Yellow, Red Edge, and Near-Infrared2) contribute to the species classification greatly (OA: 0.79 vs. 0.53). This study gains insights into the contribution of the additional spectral bands and multi-seasonal images to distinguishing species with seemingly high degrees of spectral overlap.

Near-infrared electroluminescence and stimulated emission from semiconducting nonconjugated polymer thin films

2010 ◽  
Vol 107 (2) ◽  
pp. 023103 ◽  
Author(s):  
Takeyuki Kobayashi ◽  
Martin Djiango ◽  
Werner J. Blau
Keyword(s):  
Thin Films ◽  
Near Infrared ◽  
Polymer Thin Films ◽  
Stimulated Emission

scholarly journals Near-infrared light control of membrane potential by an electron donor–acceptor linked molecule

2020 ◽  
Vol 56 (83) ◽  
pp. 12562-12565
Author(s):  
Yuta Takano ◽  
Kazuaki Miyake ◽  
Jeladhara Sobhanan ◽  
Vasudevanpillai Biju ◽  
Nikolai V. Tkachenko ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Excited States ◽  
Electron Donor ◽  
Near Infrared ◽  
Infrared Light ◽  
Light Control ◽  
Near Infrared Light ◽  
Donor Acceptor ◽  
Molecular Excited States

(π-Extended porphyrin)–fullerene linked molecules are synthesized to utilize the molecular excited states induced by near-infrared light. One of the molecules successfully alters the membrane potential.

scholarly journals Stimulated emission of near-infrared radiation in silicon fin light-emitting diode

2011 ◽  
Vol 98 (26) ◽  
pp. 261104 ◽  
Author(s):  
S. Saito ◽  
T. Takahama ◽  
K. Tani ◽  
M. Takahashi ◽  
T. Mine ◽  
...  
Keyword(s):  
Infrared Radiation ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Stimulated Emission ◽  
Near Infrared Radiation ◽  
Light Emitting

Stimulated Emission and Excited States of the I6 Donor Electron in ZnO

1971 ◽  
Vol 42 (12) ◽  
pp. 5066-5071 ◽  
Author(s):  
Takenari Goto ◽  
Dietrich W. Langer
Keyword(s):  
Excited States ◽  
Stimulated Emission
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