Search results for " Spectra"
showing 10 items of 709 documents
Effect of surface impurities on downconversion luminescence of Pr3+, Yb3+ activated SrF2 nanoparticles
2020
Abstract Pr3+,Yb3+ activated SrF2 nanoparticles synthesized by low-temperature hydrothermal method were studied. The composition and size of nanoparticles were intentionally changed by controlling synthesis conditions. After structural and morphological characterization, the spectroscopic properties of the nanoparticles were analyzed in the visible and near infrared spectra ranges. The results show correlation between the gradual change of the amount of carboxylate and hydroxyl moieties on the nanoparticle surface, varied by the size nanoparticles and the quenching of the luminescence. The size-related amount of surface quenchers is strongly connected to the decrease of the downconversion e…
Widely Tunable Polarization Modulation Instability in D2O-Filled Microstructured Optical Fiber
2021
Polarization modulation instability (PMI) is a nonlinear effect in which two pump photons with identical polarization propagating in a nonlinear medium give rise to two new photons of different frequency and orthogonal polarization with respect to the pump photons [1] . In this work, we report the experimental demonstration of broad spectral tuning of PMI generated in solid-core microstructured optical fibers (MOF) that were previously infiltrated with heavy water (D 2 O). MOFs were designed and fabricated with the appropriate dispersion characteristics to produce widely spaced PMI spectral bands when they were filled with D 2 O and pumped at 1064 nm. Heavy water was chosen due to suitable …
Free spectral range enlargement by selective suppression of optical modes in photonic crystal L7 microcavities
2015
We show an enlargement in the free spectral range (FSR) of the emission spectra of a L7 photonic crystal microcavity (PCM). The FSR enlargement is achieved by the selective modal suppression of the second cavity mode. The selective suppression is made by introducing two nano-inclusions in specific sites within the defect region that forms the cavity. We have demonstrated the suppression of the second mode of the L7-PCM, and a significant increase in the FSR of the fundamental mode. The method provides an alternative to engineer the modal structure of a photonic crystal microcavity. The large FSR-value might improve the emission properties of light sources based on photonic crystal structure…
Multi-spectral Reflection Photoplethysmography: Potential for Skin Microcirculation Assessment
2006
Technique for simultaneous recording of reflection photoplethysmography signals in broad spectral band (violet to NIR) has been developed, and its potential for assessment of blood microcirculation at various depths from the skin surface is discussed.
High-pressure synthesis of boron-rich chalcogenides B12S and B12Se
2022
The authors thank Drs. I. Dovgaliuk and T. Chauveau for assistance with Rietveld analysis; and Drs. V. Bushlya and A. Jamali for help with EDX/SEM measurements. This work was financially supported by the European Union's Horizon 2020 Research and Innovation Program under Flintstone2020 project (grant agreement No 689279).
Highly phosphorescent perfect green emitting iridium(iii) complex for application in OLEDs.
2007
A novel iridium complex, [bis-(2-phenylpyridine)(2-carboxy-4-dimethylaminopyridine)iridium(III)] (N984), was synthesized and characterized using spectroscopic and electrochemical methods; a solution processable OLED device incorporating the N984 complex displays electroluminescence spectra with a narrow bandwidth of 70 nm at half of its intensity, with colour coordinates of x = 0.322; y = 0.529 that are very close to those suggested by the PAL standard for a green emitter. Bolink, Henk, Henk.Bolink@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es ; Garcia Santamaria, Sonsoles Amor, Sonsoles.Garcia@uv.es
Structure and Phase Changes in Natural and Synthetic Magnesium Aluminum Spinel
2015
Natural spinel crystals from Ural and Pamir deposits and synthetic magnesium aluminium spinel single crystals with different stoichiometry (MgO.nAl2O3 ) grown by Verneuil method were used. The photoluminescence (PL), its excitation (PLE) and optical absorption of stoichiometric and nonstoichiometric magnesium aluminium spinel crystals containing the chromium and manganese ions and defects produced by fast neutron irradiation( fluence up to 1020cm-2, E>0.1 MeV) are investigated. The broadening of R- and N-lines takes place in synthetic stoichiometric spinel. Structure of synthetic nonstoichiometric spinels (n>1) has to be more disordered, since in addition to the site exchange …
Low-temperature studies of Cr 3+ ions in natural and neutron-irradiated g-Al spinel
2020
This study was supported by a grant from Latvian Council of Science (agreement No. LZP-2018/1-0214).
Effect of reactive ion beam etching on the photoluminescence of CdTe epitaxial layers
2008
http://link.aip.org/link/?JAPIAU/103/056108/1
Residual crystalline silicon phase in silicon-rich-oxide films subjected to high temperature annealing
2002
Structural properties of silicon rich oxide films (SRO) have been investigated by means of micro-Raman spectroscopy and transmission electron microscopy (TEM). The layers were deposited by plasma enhanced chemical vapor deposition using different SiH4/O2 gas mixtures. The Raman spectra of the as-deposited SRO films are dominated by a broad band in the region 400-500 cm-1 typical of a highly disordered silicon network. After annealing at temperatures above 1000°C in N2, the formation of silicon nanocrystals is observed both in the Raman spectra and in the TEM images. However, most of the precipitated silicon does not crystallize and assumes an amorphous microstructure. © 2002 The Electrochem…