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Sapphire Laser (sapphire + laser)

Distribution by Scientific Domains
Physics and Astronomy80%

Selected Abstracts

An injection-locked, single-mode, continuous wave Ti:Sapphire laser

LASER PHYSICS LETTERS, Issue 2 2006
T. Amthor
Abstract We report on a single-mode, continuous wave Ti:Sapphire laser injection-locked by an external cavity diode laser producing up to 1 W of single-mode output. The laser features a simple crystal temperature stabilization using a thermoelectric cooler and can be operated without any intra-cavity elements. A pump feedback mirror is used to increase efficiency. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Conversion of silver nanoprisms into colloidal nanoparticles induced by femtosecond laser pulses

LASER PHYSICS LETTERS, Issue 3 2004
Qitao Zhao
Abstract Shape transformation of silver nanoprisms in aqueous solution was studied using femtosecond laser pulses. Irradiation of a pulsed Ti:Sapphire laser at 800 nm caused the shape change of the nanoprisms from triangle into sphere, forming a stable colloid of a narrow size distribution with the particle diameters having ,10 nm. The effects of laser fluence on fragmentation and conversion were investigated using UV-vis absorption spectroscopy and transmission electron microscopy. The mechanism of laser-induced colloid formation is discussed. (© 2004 by HMS Consultants. Inc. Published exclusively by WILEY-VCH Verlag GmbH & Co.KGaA) [source]

Novel 2,1,3-Benzothiadiazole-Based Red-Fluorescent Dyes with Enhanced Two-Photon Absorption Cross-Sections

CHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2006
Shin-ichiro Kato
Abstract This paper reports the two-photon absorbing and orange-red fluorescence emitting properties of a series of new 2,1,3-benzothiadiazole (BTD)-based D,,,A,,,D-type and star-burst-type fluorescent dyes. In the D,,,A,,,D-type dyes 1,6, a central BTD core was connected with two terminal N,N -disubstituted amino groups via various ,-conjugated spacers. The star-burst-type dyes 8 and 10 have a three-branched structure composed of a central core (benzene core in 8 and triphenylamine core in 10) and three triphenylamine-containing BTD branches. All the BTD-based dyes displayed intense orange-red color fluorescence in a region of 550,689 nm, which was obtained by single-photon excitation with good fluorescent quantum yield up to 0.98 as well as by two-photon excitation. Large two-photon absorption (TPA) cross-sections (110,800 GM) of these BTD dyes were evaluated by open aperture Z -scan technique with a femtosecond Ti/sapphire laser. The TPA cross-sections of D,,,A,,,D-type dyes 2,6 with a benzene, thiophene, ethene, ethyne, and styrene moiety, respectively, as an additional ,-conjugated spacer are about 1.5,2.5 times larger than that of 1,c with only a benzene spacer. The TPA cross-sections significantly increased in three-branched star-burst-type BTDs 8 (780 GM) with a benzene core and 10 (800 GM) with a triphenylamine core, which are about 3,5 times larger than those of the corresponding one-dimensional sub-units 9 (170 GM) and 11 (230 GM), respectively. The ratios of ,/e, between three-branched and one-dimensional dyes were 6.5:3.8 (for 8 and 9) and 6.0:4.0 (for 10 and 11), which are larger than those predicted simply on the basis of the chromophore number density (1:1), according to a cooperative enhancement of the two-photon absorbing nature in the three-branched system. [source]

Enhanced luminescence and two-photon absorption of silver nano-clusters

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S1 2009
A. V. Aiboushev
Abstract Luminescence of silver nanoparticles photo-deposited on titan dioxide nanoparticles of mesoporous film is studied. Luminescence was registered under the two-photon excitation by femto-second laser pulses of Ti:sapphire laser. It was observed that Ag/ TiO2 mesoporous films have high concentration of bright luminescence spots which reveal stability to degradation under long illumination. Various configurations of silver nanoparticles are analyzed to explain the physics of bright luminescence spots ("hot spots"). Luminescence intensity reveals "hot spots" dependence on the polarization of excitation laser pulse. Properties of Ag/TiO2 system can be useful for single molecule spectroscopy and visualization of biological objects. Aapplication of Ag/ TiO2 mesoporous films for Raman scattering spectroscopy de-menstruated for the case of Rhodamine B. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]