Electronic initiation and optimization of nonlinear polarization evolution mode-locking in a fiber laser

We describe a system for automated modelocking and optimization of a fiber laser oscillator employing nonlinear polarization evolution. Using four liquid crystal variable retarders, we fully control the fiber launch and output polarization states, enabling compensation for mechanical and environmental perturbations to the fiber cavity. We demonstrate mapping of the modelocking regions for an ANDi fiber oscillator and demonstrate that local and global optimization algorithms can be used to maintain the laser in the same operating state. This technique enables robust operation of nonlinear polarization evolution modelocked fiber lasers, rivaling the stability of PM fiber lasers while maintaining the advantages of the NPE modelocking mechanism

Spatio-temporally focused femtosecond laser pulses for anisotropic writing in optically transparent materials

Simultaneous spatial and temporal focusing provides precise control of the pulse front tilt necessary for anisotropic writing and maintains this behavior over a large range of focal positions and at low numerical aperture and fluence

Spatio-temporally focused femtosecond laser pulses for nonreciprocal writing in optically transparent materials

Simultaneous spatial and temporal focusing (SSTF)provides precise control of the pulse front tilt (PFT) necessary to achieve nonreciprocal writing in glass wherein the material modification depends on the sample scanning direction with respect to the PFT. The PFT may be adjusted over several orders of magnitude. Using SSTF nonreciprocal writing is observed for a large range of axial focal positions within the sample, and nonreciprocal ablation patterns on the surface of the sample are revealed. Further, the lower numerical aperture (0.03 NA) utilized with SSTF increases the rate of writing