On-demand generation of soliton molecules through evolutionary algorithm optimization.

Combining evolutionary algorithm optimization with ultrafast fiber laser technology, we report on the self-generation of stable two-soliton molecules with controllable temporal separation. A fiber laser setup including an adjustable virtual saturable absorber achieved through nonlinear polarization evolution and an intracavity pulse shaper is used to generate two-soliton molecules with a user-defined 3-8 ps internal delay.

Rovibrational hybrid fs/ps CARS using a volume Bragg grating for N2 thermometry.

Coherent anti-Stokes Raman scattering (CARS) spectra of N2 in the hybrid femtosecond/picosecond regime have been recorded with 0.7 cm(-1) resolution. The Q-branch rovibrational structure has been resolved, making it suitable for gas-phase simultaneous rotational and vibrational thermometry applications. Resolving this spectral structure requires synchronization of a narrowband picosecond probe pulse with a broadband femtosecond pair of pump and Stokes pulses. It is achieved using a single femtosecond ytterbium-laser source and a volume Bragg grating in a compact experimental arrangement.