Sökning: "femtosecond-laser"

Visar resultat 1 - 5 av 35 avhandlingar innehållade ordet femtosecond-laser.

1. 1. Femtosecond Laser Microfabrication of Glasses and 2D Materials for Photonics and Energy Storage

   Författare :Po-Han Huang; Frank Niklaus; Göran Stemme; Kristinn Gylfason; Yves Bellouard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Femtosecond laser; 3D printing; self-organized nanogratings; micromachining; silica glass; silicon-rich glass; hydrogen silsesquioxane; photonic microdevice; microsupercapacitor; 2D materials; direct ink writing; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Femtosecond laser-based fabrication technologies have seen rapid developments in the past decades, thanks to the capability of femtosecond lasers to induce localized multiphoton absorption in materials. Multiphoton absorption can result in various material modifications that can be leveraged for additive and subtractive manufacturing. LÄS MER

3. 2. Ionization of large molecules with short laser pulses

   Författare :Mikael Kjellberg; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Photoelectron spectroscopy; Momentum mapping imaging; thermal ionization; above threshold ionization; molecular fusion; fullerenes; polyaromatic hydrocarbons; femtosecond-laser.;

   Sammanfattning : The decay dynamics of fullerenes and polyaromatic hydrocarbons (PAH) after femtosecond-laser excitation have been studied experimentally by electron momentum mapping and mass spectrometry. The electron spectra of fullerenes and large PAH-molecules were found to be exponentially decreasing with energy without any distinct peaks outside the photon energy. LÄS MER

4. 3. Experimental femtosecond-laser based investigations of model catalytic surface reactions

   Författare :Kess Marks; Henrik Öström; Stefano Bonetti; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kemisk fysik; Chemical Physics;

   Sammanfattning : In order to be able to design novel catalytic processes more efficiently, detailed understanding of the catalyst-reactant interaction and the dynamics of the microscopic reaction steps is needed. The present thesis aims to contribute to the fundamental understanding of catalyst reactant systems by means of experiments using model systems in Ultra High Vacuum (UHV). LÄS MER

5. 4. Nonlinear optical techniques for ultrafast laser diagnostics : Development of femtosecond LIF, LIGS, CARS and backward lasing

   Författare :Maria Ruchkina; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser diagnostics; femtosecond laser; nonlinear interactions; ultrafast spectroscopy; multi-photon excitation; laser-induced fluorescence; rotational coherent anti-Stokes Raman spectroscopy; laser-induced grating spectroscopy; lasing; backward lasing technique; Fysicumarkivet A:2021:Ruchkina;

   Sammanfattning : The thesis work concerns development and application of four versatile nonlinear optical techniques, based on exploiting ultrashort laser pulses, for diagnostic purposes in gases and flames. The four techniques, all laser-based, are two-photon laser-induced fluorescence (TPLIF), hybrid femtosecond/nanosecond (fs/ns) rotational coherent anti-Stokes Raman scattering (fs/ns RCARS), fs-laser-induced grating spectroscopy (fs-LIGS), and backward lasing. LÄS MER

7. 5. Photoemission Electron Microscopy for Ultrafast Nano-Optics - Femtoseconds to Attoseconds

   Författare :Erik Mårsell; Synkrotronljusfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Nanorice; Spatiotemporal imaging; Attosecond pulses; Fysicumarkivet A:2016:Mårsell; Nanowires; Silver nanostructures; Femtosecond laser pulses; PEEM; Plasmonics; Ultrafast nano-optics;

   Sammanfattning : Ultrafast nano-optics is a new and quickly evolving research field centred around the control, manipulation, and application of light on a nanometre and femtosecond scale. This can lead to improved electro-optical devices, more sensitive spectroscopy, and real-time control of chemical reactions. LÄS MER