| Title |
Third harmonic generation and six-wave mixing of femtosecond laser pulses in air / |
| Translation of Title |
Femtosekundinių lazerio impulsų trečiosios harmonikos generavimas ir šešiabangis dažnių maišymas ore. |
| Authors |
Steponkevičius, Kęstutis |
| Full Text |
|
| Pages |
48 |
| Keywords [eng] |
femtosecond laser pulses ; six-wave mixing ; third harmonic generation ; air |
| Abstract [eng] |
The main objective of doctoral dissertation was to investigate the third harmonic spectral shifts and their changes due to the refocusing and to demonstrate the third harmonic generation due to the noncollinear six-wave mixing by analyzing the characteristics (spatial, spectral and energy) and the application opportunities of this nonlinear effect by using femtosecond laser pulses in air. It was experimentally and theoretically shown that by focusing the femtosecond pulses of a ti:sapphire laser by the lenses of long focal length (2 m) in air the large spectral shifts of the pump and third harmonic waves (up to 20 nm and 50 nm, respectively) are taking place. It is shown that the refocusing of the pulse gives rise to enhanced spectral shifts of the fundamental and third harmonic waves. For the first time the phase-matched third harmonic generation in air was experimentally and theoretically demonstrated by using the noncollinear six-wave mixing wich phase-matching conditions are controlled via a change of the pump beam crossing angle. It was shown that six-wave mixing in air can be used for the temporal characterization of the femtosecond laser pulses, i.e., for the registration of the fifth-order intensity autocorrelations and frog traces of these pulses. |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Summaries of doctoral thesis |
| Language |
English |
| Publication date |
2016 |
