The noncollinear phase-matching geometries in ultra-broadband quasi-parametric amplification

Optical parametric chirped pulse amplification (OPCPA) shows great potential in producing ultrashort high-intensity pulses because of its large gain bandwidth. Quasi-parametric chirped pulse amplification (QPCPA) may further extend the bandwidth, but the behavior of QPCPA at a limited pump intensity (e.g., ≤5 GW/cm2 in a nanosecond pumped QPCPA) is not fully investigated yet. We have discussed in detail the ultra-broadband amplification and the noncollinear phase-matching geometry in QPCPA. We have modeled and developed a novel noncollinear geometry in QPCPA namely ’triple-wavelength phase-matching geometry’ which provides two additional phase-matching points around the phase-matching point at the center wavelength. Our analysis demonstrates that the triple-wavelength phase-matching geometry can support stable, ultra-broadband amplification in QPCPA. The numerical simulation results show that ultrashort pulse with a pulse duration of 7.92 fs can be achieved in QPCPA when the pump intensity is limited to 5 GW/cm2, calculated using the nonlinear coefficient of YCOB.

High-power ultrafast fiber lasers for materials processing

State-of-the-art fiber-laser systems can deliver femtosecond pulses at average powers beyond the kilowatt level and multi-mJ pulse energies by employing advanced large-mode-area fiber designs, chirped-pulse amplification, and the coherent combination of parallel fiber amplifiers. By using sophisticated coherent phase control, one or even several output ports can be modulated at virtually arbitrary power levels and switching speeds. In addition, an all-fiber setup for GHz-burst generation is described allowing to access an even wider range of laser parameters. The combination of all these approaches together with the robustness, efficiency, and excellent beam quality inherent to fiber-laser technology has the potential to strongly improve existing materials-processing applications.

Instantaneous Frequency Representation Used for CPA Laser Simulation

In the current study, we present a novel intuitive graphical method for the simulation of nonlinear effects on stretched pulses, characterized by a large time-bandwidth product. By way of example, this method allows precise determination of effects occurring in CPA (chirped pulse amplification) laser chains, such as the pre-pulse generation by the nonlinear Kerr effect. This method is not limited to first-order dispersion and can handle all resulting distortions of the generated pre-pulse.