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We report a synchronously pumped intracavity frequency-doubled optical parametric oscillator that employs a single KTiOPO(4) crystal for both parametric generation and frequency doubling. Both nonlinear processes are phase matched for the same direction of propagation in the crystal. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 745 nm, generates a green output beam at 540 nm with a 29% power conversion efficiency. Angle tuning in conjunction with pump wavelength tuning provides output tunability in the 530-585-nm range. 相似文献
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We report a femtosecond optical parametric oscillator based on a periodically poled KTiOPO(4) crystal for which quasi-phase matching is achieved with a 24-microm poling period. The singly resonant parametric oscillator, synchronously pumped by a Ti:sapphire laser at a wavelength of 758 nm, generates a signal at 1200 nm and an idler at 2060 nm. The maximum signal power conversion efficiency of the device is 22% with a pump depletion of 69%. We tune the signal wavelength over a 200-nm band by changing the cavity length. In addition, pump wavelength tuning provides output tunability in the 1000-1235-nm range. 相似文献
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The puzzle-assembly problem has many application areas such as restoration and reconstruction of archeological findings, repairing
of broken objects, solving jigsaw type puzzles, molecular docking problem, etc. The puzzle pieces usually include not only
geometrical shape information but also visual information such as texture, color, and continuity of lines. This paper presents
a new approach to the puzzle-assembly problem that is based on using textural features and geometrical constraints. The texture
of a band outside the border of pieces is predicted by inpainting and texture synthesis methods. Feature values are derived
from these original and predicted images of pieces. An affinity measure of corresponding pieces is defined and alignment of
the puzzle pieces is formulated as an optimization problem where the optimum assembly of the pieces is achieved by maximizing
the total affinity measure. A Fast Fourier Transform based image registration technique is used to speed up the alignment
of the pieces. Experimental results are presented on real and artificial data sets. 相似文献
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Barachevsky V. A. Kobeleva O. I. Venidiktova O. V. Ayt A. O. Vasilyuk G. T. Maskevich S. A. Krayushkin M. M. 《Crystallography Reports》2019,64(5):823-827
Crystallography Reports - A spectral study of the interaction between the molecules of photochromic compounds of the diarylethene class and CdSe/ZnS quantum dots (QDs), in dependence of the... 相似文献
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A. O. Ayt V. A. Barachevsky A. Duensing Ya. Yu. Fomicheva S. V. Gagarskiy H. Iglev V. V. Kiyko M. M. Krayushkin A. N. Sergeev A. V. Veniaminov V. V. Zakharov 《Optical and Quantum Electronics》2017,49(2):72
Nonlinear recording of stable fluorescent microstructures in PMMA films doped with photosensitive compound 2-(furan-2-yl)-3-(thiophen-2-carbonyl)-chromen-4-one is investigated. Energy and power density thresholds for recording stable fluorescent marks and for film destruction and photobleaching of the fluorescent marks by laser pulses were measured in wide spectral (from 530 to 620 nm) and temporal (from 80 to 7 ns) ranges. The evidences of the sequential two-step excitation mechanism for the studied dye are presented. It was shown that picosecond pulse duration range is preferable for two-photon data recording. Quasi-Gaussian and donut shaped fluorescent marks with almost the same cross-section were recorded by femtosecond pulses with rather small difference in energies. 相似文献
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Natalia L. Zaichenko Tatyana M. Valova Olga V. Venidiktova Alexander V. Lyubimov Andrey I. Shienok Liubov S. Koltsova Anton O. Ayt Galina V. Lyubimova Leonid D. Popov Valery A. Barachevsky 《Molecules (Basel, Switzerland)》2021,26(22)
Spectral-luminescence properties of a hybrid compound containing a coumarin-type spiropyran and an azomethinocoumarin fragment in toluene-acetonitrile solution in the presence of Li+, Ca2+, Zn2+ and Mg2+ ions are reported. Two excited state proton transfers can occur in the hybrid compound—the transfer of a proton from the OH group of the 7-hydroxy coumarin tautomer to the N atom of the C=N bond of the azomethine fragment leading to green ESIPT fluorescence with a maximum at 540 nm and from the OH group of the 7-hydroxy coumarin tautomer to the carbonyl group of the pyrone chromophore, which leads to the formation of the 2-hydroxyl-tautomer T of coumarin with blue fluorescence with a maximum at 475 nm. Dependence of these excited state proton transfers on the metal nature and irradiation with an external UV source is discussed. 相似文献
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