Sökning: "Optical physics"

Visar resultat 6 - 10 av 822 avhandlingar innehållade orden Optical physics.

1. 6. Nanostructured electromagnetic metasurfaces at optical frequencies

   Författare :Nils Odebo Länk; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; high-index nanophotonics; colloidal lithography; metasurfaces; geometric resonances; nanostructures; plasmonics;

   Sammanfattning : Electromagnetic metasurfaces are broadly defined as optically thin layersthat are structured on the subwavelength scale. In general, metasurfacesthus consist of nanoparticles, or other kinds of ”meta-atom”, arranged insome pattern where both the individual particle sizes and the inter-particledistances are much smaller than the wavelength. LÄS MER

3. 7. Optical parametric amplification with periodically poled KTiOPO4

   Författare :Anna Fragemann; Fredrik Laurell; Ebrahim-Zadeh Majid; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nonlinear optics; optical parametric amplification; optical parametric generation; optical parametric oscillation; Optical physics; Optisk fysik;

   Sammanfattning : This thesis explores the use of engineered nonlinear crystals from the KTiOPO4 (KTP) family as the gain material in optical parametric amplifiers (OPAs), with the aim to achieve more knowledge about the benefits and limitations of these devices. The work aims further at extending the possible applications of OPAs by constructing and investigating several efficient and well performing amplifiers. LÄS MER

4. 8. Optical Analysis of biological media - continuous wave diffuse spectroscopy

   Författare :Jan Sørensen Dam; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spatially resolved diffuse reflectance; in vitro diffuse spectroscopy; continuous wave techniques; Nuclear physics; multivariate data analysis.; Kärnfysik; Fysik; Physics; Medicin människa och djur ; Medicine human and vertebrates ; Monte Carlo simulations; light propagation models; multiple scattering; Tissue optics; tissue optical properties; Fysicumarkivet A:2000:Sörensen Dam;

   Sammanfattning : The main topic of this thesis is real-time quantification of relevant chromophores and light scattering elements in biological media. The presented methods and instrumentation are based on continuous wave (steady-state) optical measurements of (a) spatially-resolved diffuse reflectance from bulk media and (b) combined spatially-resolved and goniometric measurements of re-emitted light from thin samples. LÄS MER

5. 9. Photonic MEMS for optical information technologies

   Författare :Carlos Errando-Herranz; Kristinn B. Gylfason; Wolfram Pernice; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Micro-electro-mechanical systems MEMS ; photonics; silicon photonics; photonic integrated circuits PIC ; lithium niobate photonics; ring resonator; polarization beam splitter PBS ; microfluidic integration; lab-on-chip LoC ; optical beam steering; nonlinear optics; Electrical Engineering; Elektro- och systemteknik; Fysik; Physics; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Photonic integrated circuits (PICs) combine hundreds of optical components on a chip, and can enable fast communications, high-performance computing, and improved sensing. PICs, made by miniaturized optical waveguides, require many reconfigurable elements to enable programmable functionalities and to compensate for fabrication variations and environmental factors. LÄS MER

7. 10. Optical spectroscopy of InGaAs quantum dots

   Författare :Arvid Larsson; Per Olof Holtz; Artur Zrenner; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; semiconductor; optical properties; spin; transport; wetting layer; polarization; kvantprick; halvledare; optiska egenskaper; spin; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Materials science; Teknisk materialvetenskap; Condensed matter physics; Kondenserade materiens fysik; Semiconductor physics; Halvledarfysik;

   Sammanfattning : The work presented in this thesis deals with optical studies of semiconductor quantum dots (QDs) in the InGaAs material system. It is shown that for self-assembled InAs QDs, the interaction with the surrounding GaAs barrier and the InAs wetting layer (WL) in particular, has a very large impact on their optical properties. LÄS MER