Sökning: "ultrashort pulses"
Visar resultat 1 - 5 av 23 uppsatser innehållade orden ultrashort pulses.
1. Quantum Optical Description of High-order Harmonic Generation
Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionenSammanfattning : High-order Harmonic Generation (HHG) is a highly non-linear process in which an atom interacts with a strong laser field. The laser field lowers the atomic potential barrier allowing bound electrons to escape into the continuum through tunnel ionization, propagate, and, with some probability, recombine with the parent ion. LÄS MER
2. Towards a setup for narrowband terahertz generation through difference-frequency mixing of chirped ultrashort pulses
Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionenSammanfattning : Terahertz radiation is a useful tool for inducing lower-energy excitations in matter, where it can be used to cause structural changes through direct interaction with the crystal lattice. Sub-picosecond optical pulses can be used to generate intense broadband terahertz pulses through optical rectification in nonlinear crystals, reaching peak electric fields of several MV/m and conversion efficiencies as high as a few percent. LÄS MER
3. Spectral broadening of 4 mJ femtosecond pulses using a bulk multi-pass cell
Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionenSammanfattning : Nonlinear optical effects can be used for spectral broadening, which the basis of the field of post-compression of laser pulses. When the intensity of light becomes high enough the refractive index becomes intensity dependent, and as the intensity often varies both with position and time so does the refractive index. LÄS MER
4. Measuring the Pulse Duration and the Time-Dependent Polarisation State of Ultrashort Laser Pulses with the D-Scan Technique
Master-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/AtomfysikSammanfattning : Ultrashort laser pulses with time-dependent polarisation states have many applications, such as the generation of isolated attosecond pulses and the study of the optical chirality of molecules. In this project the polarisation gate, built from two quarter-wave plates of different orders, is thoroughly characterised in experiment and simulation. LÄS MER
5. Dispersion management and characterization of ultrashort laser pulses for the optimization of parametric processes
Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionenSammanfattning : This thesis set out to continue the development of a short-wave infrared (SWIR) optical parametric amplifier (OPA). The system is based on a Yb-ber chirped pulse amplification (CPA) laser delivering 400 fs long pulses, centered around 1030 nm, at 200 kHz repetition rate and 40 W average power. LÄS MER