Sökning: "Terahertz radiation"
Visar resultat 1 - 5 av 19 avhandlingar innehållade orden Terahertz radiation.
1. Ultrafast spin dynamics at the nanoscale : using coherent X-ray and terahertz radiation
Sammanfattning : The field of ultrafast magnetism is driven by the growing need for faster and more efficient magnetic data storage, which comprises the vast majority of the digital information worldwide. However, after more than two decades of intense research, the understanding of the fundamental physical processes governing the transfer of angular momentum necessary for magnetic switching, is still lacking, partially hampered by the appropriate experimental tools. LÄS MER
2. Photonic terahertz-wave generation, radiation and quasioptical integration
Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER
3. Terahertz radiation as a pump and probe for studying low frequency vibrations in proteins
Sammanfattning : Many functionally important structural changes in proteins proceed along the direction of their lowest frequency vibrations. These vibrations correspond to picosecond collective dynamics. Establishing the fundamental relationship between these vibrations and protein function remains a challenge within biophysics. LÄS MER
4. Terahertz spin dynamics in metallic thin film ferromagnets
Sammanfattning : The past two decades have witnessed an increasing interest in understanding and controlling materials at the pico- and femtosecond time scales, the so-called ultrafast regime. Among the broad field of condensed matter physics, magnetism and magnetic materials have attracted much interest both from a fundamental and an applied perspective. LÄS MER
5. Ultrafast spin, lattice, and electron dynamics in thin metallic films : in the terahertz, near-infrared, and extreme ultraviolet regimes
Sammanfattning : In this thesis, we studied the ultrafast spin and electron dynamics triggered by electromagnetic radiation belonging to three different regions of the electromagnetic spectrum, namely terahertz, near-infrared and extreme ultraviolet. By performing pump–probe measurements, we explored the role of the lattice in ultrafast spin and electron dynamics in metallic thin films. LÄS MER