Sökning: "upconversion"

Visar resultat 1 - 5 av 30 avhandlingar innehållade ordet upconversion.

  1. 1. Advancing Upconversion Emissions for Biomedical Imaging

    Författare :Haichun Liu; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; upconverting nanoparticles; luminescence; fluorescence; inverse problem; biomedical optics; biomedical imaging; photon migration; upconversion; tomography; saturation; Fysicumarkivet A:2014:Liu;

    Sammanfattning : During the past decade, upconverting nanoparticles (UCNPs) doped with rare earth ions have become an important class of fluorescence contrast agents for molecular imaging, due to their unique properties. Their property of anti-Stokes luminescence, with both the excitation and emission wavelengths close to the optimal for biomedical imaging, has been extensively explored in various biomedical applications. LÄS MER

  2. 2. Upconversion Detection for Improved Nonlinear Mid-infrared Spectroscopy in Flames

    Författare :Rasmus Lyngbye Pedersen; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; infrared; upconversion; degenerate four wave mixing; hydrogen cyanide; polarisation spectroscopy;

    Sammanfattning : This thesis deals with the addition of upconversion detection to non-linear mid-infrared laser spectroscopy techniques. The techniques investigated here are degenerate four wave mixing (DFWM) and infrared polarization spectroscopy (IRPS). LÄS MER

  3. 3. Photon Upconversion in Heavily Doped Semiconductors

    Författare :Kilian Mergenthaler; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; III-V semiconductor materials; nanowires; photoluminescence; Photon upconversion; semiconductors; doping; Fysicumarkivet A:2016:Mergenthaler;

    Sammanfattning : In this thesis the luminescence properties of highly doped semiconductors are studied with focus on degenerately n-doped InP. It is demonstrated how photoluminescence measurements on degenerately doped semiconductors allow an estimation of the doping concentration without need for electrical contacts. LÄS MER

  4. 4. Upconversion in Er doped silica : - characterization and modeling

    Författare :Dmitry Khoptyar; Bozena Jaskorszynska; Anders Bjarklev; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Electrical engineering; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : Further increase of erbium concentrations in Er-doped amplifiers and lasers is needed for the design of efficient, reliable, compact and cost-effective components for telecommunications and other photonic applications. However, this is hindered by Er concentration dependent loss mechanism known as upconversion. LÄS MER

  5. 5. Radiative Properties of Rare Earth Elements - Free and Bound in Crystals

    Författare :Huailiang Xu; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Laser Spectroscopy; Upconversion; Lifetimes; Atomic and molecular physics; Atom- och molekylärfysik; Laser technology; Laserteknik; Rare earth Elements; Fysicumarkivet A:2004:Xu;

    Sammanfattning : This thesis is devoted to fundamental aspects, and to spectroscopic applications of radiative properties in free atoms and ions, as well as in ions doped into crystals. Using the time-resolved laser-induced fluorescence technique, measurements of radiative lifetimes for rare earth elements have been performed in neutral Pr, Nd, Tm, and in singly ionized Sm, Er, Nd, Tm, Yb, as well as in doubly ionized Tm and Tb ions. LÄS MER