Effects of vacuum exposure on stress and spectral shift of high reflective coatings

Photoswitching of phytochrome photoreceptors between red-absorbing (Pr) and far-red absorbing (Pfr) states triggers light adaptation of plants, bacteria and other organisms. Using quantum chemistry, we elucidate the color-tuning mechanism of phytochromes and identify the origin of the Pfr-state red-shifted spectrum. Spectral variations are explained by resonance interactions of the protonated linear tetrapyrrole chromophore. In particular, hydrogen bonding of pyrrole ring D with the strictly conserved aspartate shifts the positive charge towards ring D thereby inducing the red spectral shift. Our MD simulations demonstrate that formation of the ring D–aspartate hydrogen bond depends on interactions between the chromophore binding domain (CBD) and phytochrome specific domain (PHY). Our study guides rational engineering of fluorescent phytochromes with a far-red shifted spectrum.

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STUDY OF ANTI-REFLECTIVE COATINGS T а 2 O 5 / SiO 2 FOR IMPROVING THE EFFICIENCY OF MODERN SOLAR CELLS FOR SPACE APPLICATIONS

Siberian Journal of Science and Technology ◽

10.31772/2587-6066-2018-19-1-59-65 ◽

2018 ◽

Vol 19 (1) ◽

pp. 59-65 ◽

Cited By ~ 1

Author(s):

M.A. Genali ◽

◽

S.K. Sharov ◽

A.A. Lebedev ◽

N.T. Vagapova ◽

...

Keyword(s):

Solar Cells ◽

Space Applications ◽

Reflective Coatings

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Strong coupling of a plasmonic nanoparticle to a semiconductor nanowire

Nanophotonics ◽

10.1515/nanoph-2021-0214 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Yingying Jin ◽

Liu Yang ◽

Chenxinyu Pan ◽

Zhangxing Shi ◽

Bowen Cui ◽

...

Keyword(s):

Strong Coupling ◽

Coupled System ◽

Resonance Wavelength ◽

Transverse Magnetic ◽

Spectral Shift ◽

Au Nanoparticle ◽

Localized Surface Plasmon ◽

Nanowire Diameter ◽

Plasmonic Nanoparticle ◽

Au Nanosphere

Abstract By placing a single Au nanoparticle on the surface of a cadmium sulfide (CdS) nanowire, we demonstrate strong coupling of localized surface plasmon resonance (LSPR) modes in the nanoparticle and whispering gallery modes (WGMs) in the nanowire. For a 50-nm-diameter Au-nanosphere particle, strong coupling occurs when the nanowire diameter is between 300 and 600 nm, with a mode splitting up to 80 meV. Using a temperature-induced spectral shift of the resonance wavelength, we also observe the anticrossing behavior in the strongly coupled system. In addition, since the Au nanosphere has spherical symmetry, the supported LSPR mode can be selectively coupled with transverse electric (TE) and transverse magnetic (TM) WGMs in the nanowire. The ultracompact strong-coupling system shown here may provide a versatile platform for studying hybrid “photon–plasmon” nanolasers, nonlinear optical devices, and nanosensors.

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Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle

Scientific Reports ◽

10.1038/s41598-021-88117-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aizhan Issatayeva ◽

Aida Amantayeva ◽

Wilfried Blanc ◽

Daniele Tosi ◽

Carlo Molardi

Keyword(s):

Performance Analysis ◽

Minimally Invasive ◽

Optical Fibers ◽

Single Mode ◽

Spectral Shift ◽

Shape Reconstruction ◽

Minimally Invasive Surgical ◽

Working Principle ◽

Doped Fibers ◽

Distributed Measurement

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

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Determination of pseudo-refractive index in self-assembled ligand layers from spectral shift of surface plasmon resonances in colloidal silver nanoplates

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2020-1786 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Pavel Malakhovsky ◽

Dmitry Murausky ◽

Dmitry Guzatov ◽

Sergey Gaponenko ◽

Mikhail Artemyev

Keyword(s):

Refractive Index ◽

Surface Plasmon ◽

Mie Theory ◽

Spectral Shift ◽

Localized Surface Plasmon ◽

Clear Trend ◽

Silver Nanoplates ◽

Assembled Monolayers ◽

Self Assembled

Abstract We examined systematically how self-assembled monolayers (SAMs) of different mercaptoacids affect the spectral shift of the localized surface plasmon resonance in silver nanoplates and nanospheres. We observed a clear trend in the magnitude of a redshift with a molecular length or the SAM thickness within a homologous series of aliphatic mercaptoacids: the thicker shell the stronger the red shift. Using classic Mie theory for plasmonic core-dielectric shell spheres and oblate spheroids we developed the method for determination of a pseudo-refractive index in SAM of different molecules and obtained a good correlation with the reference refractive indices for bulk long-chain aliphatic acids, but only in case of silver nanoplates. Calculations for silver core–shell nanospheres gave overestimated values of refractive index perhaps due to restrictions of Mie theory on the minimum particle size.

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Ionophore-sensitive spectral shift of carotenoid induced by ferricyanide in chromatophores from Rhodopseudomonas sphaeroides

Plant and Cell Physiology ◽

10.1093/oxfordjournals.pcp.a076023 ◽

1980 ◽

Keyword(s):

Spectral Shift ◽

Rhodopseudomonas Sphaeroides

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Carboxyhemoglobin determination by second-derivative spectroscopy.

Clinical Chemistry ◽

10.1093/clinchem/31.2.279 ◽

1985 ◽

Vol 31 (2) ◽

pp. 279-281 ◽

Cited By ~ 17

Author(s):

J Parks ◽

H G Worth

Keyword(s):

Spectrum Analysis ◽

Spectral Shift ◽

Zero Order ◽

Reduced Form ◽

Second Derivative ◽

Derivative Spectrum ◽

Derivative Spectroscopy ◽

Set Up ◽

Second Derivative Spectroscopy

Abstract In this procedure hemoglobin is converted to its reduced form and the magnitude of the zero-order spectral shift of the reduced hemoglobin peak at 430 nm to the carboxyhemoglobin peak at 418 nm is determined by second-derivative spectrum analysis. The method is simple, straightforward to set up, and rapid. A result may be obtained within 15 min of receiving the sample. It is sufficiently sensitive to differentiate carboxyhemoglobin concentration in the blood of smokers and nonsmokers.

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