| Abstract [eng] |
Broadband infrared light laser sources are of great interest in many applications, such as spectroscopy, fiber communications, optical parametric chirped pulse amplification (OPCPA) or light detection and ranging (LIDAR). A broadband radiation can be obtained using optical fibers, periodically poled crystals near degeneracy or in aperiodically poled crystals. The goal of this work was to develope a broadband infrared picosecond source for sum frequency generation spectroscopy with a tunable 500 cm-1 spectrum in 2.5 – 5.0 µm range. This should reduce data acquisition time, increase system stability and lower noise when compared with the currently used narrow linewidth spectrometer configuration. The setup was based on quasi-phase-matched (QPM) aperiodically poled lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) crystals specifically designed for generation and amplification of broadband signal. It was revealed the seed wave is needed for efficient parametric generation and good quality idler beam shape in 2.5 – 5.0 µm range in aperiodically poled lithium niobate. Broad spectra have been obtained in 2.5 – 3.3 µm (> 500 cm-1) and 3.3 – 3.8 µm (> 200 cm-1) ranges. The developed source was tested for sum frequency generation in ODT (octadecanetiol – CH3(CH2)17SH) sample. |
