Sökning: "Poling"

Visar resultat 6 - 10 av 28 avhandlingar innehållade ordet Poling.

1. 6. QPM Devices in KTA and RKTP

   Författare :Andrius Zukauskas; Carlota Canalias; Moti Katz; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; QPM; periodic poling; KTP;

   Sammanfattning : Even though KTiOPO4 (KTP) is considered to be one of the best nonlinear materials for quasi phase matched (QPM) frequency conversion in the visible and the near-infrared spectral regions, its use is often limited by poor material homogeneity, high ionic conductivity, a considerable linear absorption and photochromatic damage. On the other hand, the improved material homogeneity and the lower ionic conductivity of bulk Rb-doped KTP (RKTP) make this material an ideal alternative for fabrication of fine-pitch QPM gratings, while the arsenate isomorph KTiOAsO4 (KTA) promises a better performance in the green spectral region and adds the advantage of a wider transparency window in the infrared. LÄS MER

3. 7. Advanced nano- and microdomain engineering of Rb-doped KTiOPO4 for nonlinear optical applications

   Författare :Charlotte Liljestrand; Carlota Canalias; Sunao Kurimura; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; KTiOPO4; nonlinear optics; MOPO; quasi-phase matching; SHG; ferroelectrics; domain structuring; periodic poling; Fysik; Physics;

   Sammanfattning : Fine-pitch ferroelectric domain gratings are extensively used for generation of light in the visible and near-infrared spectral regions through quasi-phase matched (QPM) frequency conversion. Sub-μm QPM devices enables demonstration of nonlinear optics with counterpropagating waves, a field of nonlinear optics which remains sparsely explored due to the difficulty of fabricatinghigh quality gratings. LÄS MER

4. 8. The importance of body-mass exponent optimization for evaluation of performance capability in cross-country skiing

   Författare :Tomas Carlsson; Michail Tonkonogi; Christer Malm; Klavs Madsen; Högskolan Dalarna; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; allometric scaling; power-function modelling; maximal oxygen uptake; body mass; elite skiers; distance skiing; lactate threshold; double poling; sprint skiing; competition; power output; time trial; Hälsa och välfärd; Health and Welfare;

   Sammanfattning : Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. LÄS MER

5. 9. Nonlinear response in engineered optical materials

   Författare :Gustav Strömqvist; Valdas Pasiskevicius; Peter Smith; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nonlinear optics; nonlinear index of refraction; double tungstates; periodic poling; KTiOPO4; quasi-phase matching; parametric down-conversion; mirrorless optical parametric oscillators;

   Sammanfattning : Material and structure engineering are increasingly employed in active optical media,in this context defined as media capable of providing laser or/and optical parametric gain. For laser materials, the main aim of the engineering is to tailor the absorption and emission cross sections in order to optimise the laser performance. LÄS MER

7. 10. Quasi-Phasematched nonlinear processes in KTiOPO4 isomorphs

   Författare :Anna Fragemann; KTH; []
   Nyckelord :nonlinear optics; optical parametric oscillator; optical parametric amplifier; KTiOPO4; RbTiOPO4; quasi-phasematched; electric field poling;

   Sammanfattning : This thesis explores the use of nonlinear crystals from theKTiOPO4(KTP) family with the aim to extend the possibleapplications for laser sources and to gain more knowledge aboutthe material’s benefits and limits. The work focussed onoptical parametric oscillators (OPOs) and optical parametricamplifiers (OPAs), which employ second order nonlinearprocesses. LÄS MER