scholarly journals Characterization of Optically-Reconfigurable Metasurfaces by a Free Space Microwave Bistatic Technique

2020 ◽  
Vol 10 (12) ◽  
pp. 4353
Author(s):  
Houssemeddine Krraoui ◽  
Charlotte Tripon-Canseliet ◽  
Ivan Maksimovic ◽  
Stefan Varault ◽  
Gregoire Pillet ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Power ◽  
Frequency Selective Surface ◽  
Infrared Region ◽  
Photon Absorption ◽  
60 Ghz ◽  
Frequency Range ◽  
Specific Incident ◽  
Absorption Phenomenon

Microwave performance extraction of optically-controlled squared frequency-selective surface (FSS) structures printed on highly resistive (HR) silicon substrate are presented, from a innovative bistatic microwave photonic characterization technique operating in the 40 to 60 GHz frequency range, commonly used for radar cross section (RCS) measurements. According to typical physical photon absorption phenomenon occurring in photoconductive materials, these structures demonstrate experimentally a bandpass filtering frequency response cancellation through reflection coefficient measurements, under specific incident collective illumination in the Near-infrared region (NIR). This behaviour is attributed to their microwave surface impedance modification accordingly to the incident optical power, allowing ultrafast reconfigurability of such devices by optics

Three-Photon Induced Optical Limiting of a Novel Multibranched Nonlinear Chromophore Containing Carbazole Moiety

2012 ◽  
Vol 170-173 ◽  
pp. 2851-2854 ◽  
Author(s):  
Zhi Yuan Hu ◽  
Fu Quan Guo ◽  
Bin Guo ◽  
Hao Liang
Keyword(s):  
Cross Section ◽  
Near Infrared ◽  
Optical Power ◽  
Picosecond Laser ◽  
Infrared Region ◽  
Photon Absorption ◽  
Picosecond Laser Pulse ◽  
Transmission Measurements ◽  
Near Infrared Region ◽  
Optical Power Limiting

A novel multibranched nonlinear chromophore containing carbazole moiety，4, 4´, 4´´-tris(9-(3,6-tert-butyl)carbazyl-trans-styryl) -1, 3, 5-triphenylbenzene (TCSTPB)，was synthesized and characterized by 1HNMR and elemental analysis. One-photon absorption in chloroform shows the optical transparent property of the chromophore in the near infrared region. The properties of optical power limiting induced by three-photon absorption (3PA) are demonstrated. Large 3PA coefficients and the corresponding 3PA molecular cross section as high as 10-74 cm6 s2 was obtained pumped by picosecond laser pulse at 1.06 μm from nonlinear transmission measurements.

Synthesis and characterization of the leaf-like Cu2O/CuO mixed phase nanosheets array

2019 ◽  
Vol 33 (36) ◽  
pp. 1950461 ◽  
Author(s):  
Yan Qi ◽  
Bingqian Bi ◽  
Yilin Yan ◽  
Lecheng Tian
Keyword(s):  
Near Infrared ◽  
Wavelength Region ◽  
Infrared Region ◽  
Mixed Phase ◽  
Synthesis And Characterization ◽  
Average Height ◽  
Xps Analysis ◽  
Sem Images ◽  
Near Infrared Region

In this study, a leaf-like [Formula: see text] mixed phase nanosheets array was successfully prepared by anodization. XRD, EDS, and XPS analysis confirmed the formation of [Formula: see text] mixed phase nanostructures. SEM images indicate that the fabricated [Formula: see text] mixed phase nanosheets almost grow vertically on the substrate. The average height of nanosheets is approximately 500 nm. The optical absorption of the mixed phase covers the entire wavelength region of visible light and a little part of the near-infrared region of short wavelength.

scholarly journals Spectral Characterization of Difusse Par Irradiance under Tipuana Tipu Shading

2018 ◽  
Vol 75 (1) ◽  
pp. 19
Author(s):  
Gonzalo GURREA-YSASI ◽  
Vicente BLANCA ◽  
Ana FITA ◽  
Jaime PROHENS ◽  
Inmaculada FITA ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Tree Canopies ◽  
Common Tree ◽  
Soil Level

Tipa (Tipuana tipu) is a common tree in gardens and carparks, although the shading effect of its canopy must be still characterised to assess the decrease of temperature and quality of irradiance. This work is a preliminary study aimed to assess the effect of shading of tree canopies on the diffuse irradiance pattern received at the soil level in comparison to other conditions. The shade provided by a group of Tipa trees, located at the Universitat Politècnica de València (Valencia, Spain), was evaluated in this experiment and compared to cloudy days and direct sun. Photosynthetic Photon Flux Density (PPFD) and red/near infrared ratios were recorded with a portable spectrometer. Measurements were recorded in January and February 2017, at 10h, 13h and 16h. Depending on the region of the spectrum and time of the day, PPFD values ranged from 0.05 to 0.42, 0.40 to 1.14, and 0.94 to 3.90 μmol·m-2·s-1, for Tipa shade, cloudy days and direct sun, respectively. The spectral analysis of PPFD in cloudy days revealed maximum values in the green region and minimum at near infrared region, while maximum PPFD for tipa shade was mostly found at near infrared, revealing higher importance of this spectral region compared to cloudy days.

COMPARATIVE STUDIES ON THE THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF THREE METAL-ORGANIC COMPOUNDS

2011 ◽  
Vol 20 (02) ◽  
pp. 229-236 ◽  
Author(s):  
PENGFEI ZHANG
Keyword(s):  
Near Infrared ◽  
Heavy Atom ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Optical Limiting ◽  
Infrared Region ◽  
Photon Absorption ◽  
Third Order ◽  
The Third ◽  
Planar Transition

The third-order optical nonlinearities of three planar transition metal ( Ni, Cu and Pd ) compounds with rigid quadridentate Schiff base derived from S-benzyl dithiocarbazate, were investigated systematically by Z-scan technique with picosecond laser pulses at 1064 nm. The three compounds exhibit both strong two-photon absorption and effective self-focusing performance. Due to the heavy atom effect, the second hyperpolarizability of PdZ molecule (〈γ〉 = 1.2 × 10-29 esu) was found to be the highest compared to that of the other two molecules. The optical limiting properties were also measured, and the results suggest that PdZ may be a promising candidate for the application to optical limiting in the near-infrared region.

Darstellung, spektroskopische und elektrochemische Charakterisierung von Pentachloromonocarbonylosmat(IV), [OsCl5(CO)]- / Preparation, Spectroscopical and Electrochemical Characterization of Pentachlorom onocarbonylosm ate(IV), [OsCl5(CO)]-

1986 ◽  
Vol 41 (1) ◽  
pp. 25-31 ◽  
Author(s):  
M. Bruns ◽  
W. Preetz
Keyword(s):  
Near Infrared ◽  
Point Group ◽  
Visible Region ◽  
Infrared Region ◽  
Isotopic Substitution ◽  
Standard Potential ◽  
Racah Parameter ◽  
Charge Transfer Transitions ◽  
Near Infrared Region

The first carbonyl compound of quadrivalent osmium [OsCl5(CO)]- is prepared by chlorination of trans-[OsX4(CO)2]- (X = Br, I) dissolved in CH2Cl2. It is reduced immediately by Br- and I- to give [OsCl5(CO)]2-. The standard potential [OsCl5(CO)]-/ [OsCl5(CO)]2- in acetonitrile referred to the saturated mercury-mercurous sulphate electrode is 0.623 V. The IR and Ra bands of [OsCl5(CO)]- are assigned according to point group C4v. Compared with the corresponding Os(III) complex there is a shift to higher frequencies of ν(CO) and ν(OsCI) of about 170 and 25 cm-1, whereas ν(OsC) and δ(OsCO) are lowered by 158 and 110cm-1, respectively. The electronic absorption spectrum shows six d - d bands coupled with vibrations in the near infrared region. The O - O transitions are calculated from the vibrational fine structure, taking into consideration shifts by 13C isotopic substitution. The lowest levels are confirmed by peaks in the electronic Raman spectrum. From the estimated Racah parameter B = 280 cm-1 the low nephelauxetic ratio β55 = 0.41 is deduced indicating the high covalency in [OsCl5(CO)]-. Owing to the strong oxidizing character of Os(IV) the intensive charge transfer transitions in the visible region are shifted bathochromicly by about 4000 cm1 in relation to corresponding bands of [OsCl5(CO)]2-.

scholarly journals Near-infrared dyes for two-photon absorption in the short-wavelength infrared: strategies towards optical power limiting

2021 ◽  
Author(s):  
Simon Pascal ◽  
Sylvain David ◽  
Chantal Andraud ◽  
Olivier Maury
Keyword(s):  
Spectral Range ◽  
Short Wavelength ◽  
Near Infrared ◽  
Optical Power ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Infrared Spectral Range ◽  
Infrared Spectral ◽  
Optical Power Limiting

The recent advances in the field of two-photon absorbing chromophores in the short-wavelength infrared spectral range (SWIR 1100–2500 nm) are summarized, highlighting the development of optical power limiting devices in this spectral range.

scholarly journals On the Fly” Characterization of YbIII:ErIII Co-Doped Upconversion Nanoparticle Nonlinear Optical Response from Single-Particle Trajectories

2021 ◽  
Author(s):  
Isabela Cavalcante ◽  
María Claudia Marchi ◽  
Fernando Sigoli ◽  
Paulo Cesar de Sousa Filho ◽  
Beatriz C. Barja ◽  
...  
Keyword(s):  
Single Particle ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Stochastic Dynamics ◽  
Optical Power ◽  
Spectroscopic Characterization ◽  
Structure Property ◽  
Individual Nanoparticles ◽  
Co Doped

<p> Spectroscopic characterization of individual nanoparticles is essential for understanding their structure-property relationship and for applications. Upconversion nanoparticles (UCNPs) in condensed phases can undergo both nonlinear optical and stochastic dynamics when interacting with near-infrared sources. By integrating optical trapping microspectroscopy, stochastic dynamics and light-matter interactions experiments and simulations, in the present work we study how individual trajectories of YbIII:ErIII co-doped UCNPs can be used to perform “on the fly” characterization of their nonlinear optical power-law response upon near-infrared excitation. We illustrate the methodology in the case of freely diffusing and optically trapped UCNPs as well as with particles bound to the substrate. The approach presented in this work can be applied to UCNPs with varying composition and morphological features, particularly in single-particle studies.</p>

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