| Abstract [eng] |
This dissertation is intended for parametric light oscillators synchronously pumped by femtosecond pulses of Yb:KGW laser (SPOPO), which generate tunable radiation in the near infrared spectral range. Such devices generate pulses at a high repetition rate (>50 MHz) and have recently become increasingly used in nonlinear microscopy and spectroscopy. Various periodically polished nonlinear crystals (PPLN, MgO: PPLN, PPKTP) were tested and the peculiarities of the radiation generated by such SPOPO were investigated. In the case of PPKTP SPOPO, the 40 % conversion efficiency from pump power into signal power in the range of ∼1500 nm was demonstrated. It was shown that an increasing of a transmittance of the output mirror of the SPOPO, which cavity is characterized by total negative group delay dispersion, results in a shortening of the generated signal pulses. In this work, the resistance of nonlinear crystals used in SPOPO devices to high-repetition laser radiation was investigated and a nonlinear absorption measurement method was demonstrated, which allows to estimate the limits of such resistance without damaging these crystals. Also, the investigation of dependency of continuum generation in the optical fiber on a pump wavelength in the region of zero dispersion wavelength using PPKTP SPOPO pulses, tunable in the 1,45-1,8 µm spectral range, was demonstrrated. |
