| Abstract [eng] |
This thesis describes studies on the generation of femtosecond pulses in the 1.1–3 µm spectral range (SWIR) by supercontinuum (SC), optical parametric (OPCPA), and stimulated Raman scattering amplifiers (SR), with pumping by picosecond-duration 1030 nm pulses. This work explores the synergy of combining various nonlinear effects to efficiently generate SWIR femtosecond pulses. The first part of the thesis present a mJ-class SWIR OPCPA laser system developed during the study, where the seed source is a broadband SC. In the final stage of the system, an outstanding pump-to-signal conversion efficiency of up to ~25% was achieved, resulting in output pulse energy of ~2.2 mJ. Without active spectral phase control, the pulses were compressed up to ~38 fs. The second part outlines investigated approaches to improve SRS efficiency in the transient regime by extending the pump spectral bandwidth in the NIR region. It was demonstrated transient cascade SRRS combs in compressed hydrogen with an efficiency of up to ~52% covering ~1.1 – 1.4 μm wavelength. Additionally, adjacent vibrational Stokes mode spectral synthesis was achieved in KGW crystals, where the composite spectral bandwidth of the signal increased ~23 times compared to the pump pulses, with a conversion efficiency of ~35%. The third part of the thesis describes studies combining SWIR OPCPA with SRS in KGW crystals and hydrogen. In the first case, energy transfer from signal to idler was demonstrated, achieving a conversion efficiency of ~25%. In the second case, revealed that positively chirped broadband SC seed pulses contribute to the extension of the SRRS spectral bandwidth to longer wavelengths compared to negatively chirped ones. |
