Sökning: "two-photon excitation"

Visar resultat 1 - 5 av 33 avhandlingar innehållade orden two-photon excitation.

1. 1. Two-Photon Excited Fluorescence Depolarisation : Experimental and Theoretical Development

   Författare :Linus Ryderfors; Emad Mukhtar; Lennart B.-Å. Johansson; Yehudi K. Levine; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-photon excitation; Fluorescence; Fluorescence depolarisation; Fluorescence anisotropy; Time-correlated single photon counting; Gold nanoparticles; Rotational diffusion; Excited state symmetry; Extended Förster theory; Orientation correlation functions; Donor-donor energy migration DDEM ; Chemical physics; Kemisk fysik;

   Sammanfattning : We have studied fundamental aspects of time-resolved two-photon excited fluorescence depolarisation. The thesis presents experimental as well as theoretical progress. LÄS MER

3. 2. Phase Modulation Two-Photon Microscopy of Hybrid Halide Perovskite

   Författare :Qi Shi; NanoLund: Centre for Nanoscience; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Phase modulation; two-photon microscopy; perovskite; trap; carrier recombination;

   Sammanfattning : Recently, intense research activities have been focused on solution-processed hybrid lead halide perovskite semiconductors which are being developed for the solar-cell, light emitting diode (LED), and lasing applications. To optimize and fabricate a competitive perovskite-based optoelectronic device, the fundamental studies of the electronic structure, photo-generated carrier dynamics as well as the photoluminescence (PL) & photocurrent (PC) response are necessary and of great significance. LÄS MER

4. 3. Two-Photon Absorption and Photorefraction in Semiconductors and Ferroelectrics

   Författare :Johan Bergquist; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Two-photon absorption spectra of Al0.4Ga0.6As/GaAs quantum wells in static electric fields are investigated experimentally. A drastic field-induced increase in the absorption peaks at energies close to half the bandgap energy is reported for the first time. LÄS MER

5. 4. A new approach to the analyses of fluorescence depolarisation experiments in the presence of electronic energy transport

   Författare :Oleg Opanasyuk; Lennart B-Å Johansson; Per-Olof Westlund; Yehudi Levine; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; electronic energy transfer; donor-donor energy migration; extended Förster theory; fluorescence depolarisation; two-photon excitation; computer simulations; genetic algorithms; fysikalisk kemi; Physical Chemistry;

   Sammanfattning : A new and general procedure is described for a detailed analysis of time-resolved fluorescence depolarisation data in the presence of electronic energy migration. An isotropic ensemble of bifluorophoric molecules (D1-R-D2) has been studied to demonstrate its utility. LÄS MER

7. 5. Electronic Energy Migration/Transfer as a Tool to Explore Biomacromolecular Structures

   Författare :Therese Mikaelsson; Lennart B.-Å. Johansson; Kristine Kilså; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fluorescence; electronic energy transfer; two-photon excitation; small ribosomal protein S16; macromolecular crowding; dextran 20; fysikalisk kemi; Physical Chemistry;

   Sammanfattning : Fluorescence-based techniques are widely used in bioscience, offering a high sensitivity and versatility. In this work, fluorescence electronic energy migration/ transfer is applied to measure intramolecular distances in two types of systems and under various conditions. LÄS MER