53 W average power CEP-stabilized OPCPA system delivering 5.5 TW few cycle pulses at 1 kHz repetition rate.

We present a high peak and average power optical parametric chirped pulse amplification system driven by diode-pumped Yb:KGW and Nd:YAG lasers running at 1 kHz repetition rate. The advanced architecture of the system allows us to achieve >53 W average power combined with 5.5 TW peak power, along with sub-220 mrad CEP stability and sub-9 fs pulse duration at a center wavelength around 880 nm. Broadband, background-free, passively CEP stabilized seed pulses are produced in a series of cascaded optical parametric amplifiers pumped by the Yb:KGW laser, while a diode-pumped Nd:YAG laser system provides multi-mJ pump pulses for power amplification stages. Excellent stability of output parameters over 16 hours of continuous operation is demonstrated.

Aberrations induced by anti-ASE cap on thin-disk active element.

Optical aberrations induced in thin-disk laser elements with an undoped layer, performing as an anti-ASE cap, are analyzed. A numerical model, used for calculations of the optical path difference (OPD) induced by temperature distribution inside the laser element and by deformation of surfaces, was confirmed experimentally. Results of numerical modeling manifest that adding an undoped layer on the thin-disk has detrimental effect on the reflected laser beam brightness and scaling. It is also shown that brightness of a thin-disk laser may be enhanced by the use of the Gaussian pump beam profile.

Corneal shaping and ablation of transparent media by femtosecond pulses in deep ultraviolet range.

PURPOSE: To assess the performance of a newly developed solid-state femtosecond ultraviolet (UV) laser system in corneal ablation. SETTING: Vilnius University, Laser Research Centre, Vilnius, Lithuania. METHODS: Femtosecond pulses in the deep UV range (205 nm) were obtained by the generation of the fifth-harmonic of an amplified Yb:KGW laser system (fundamental output at 1027 nm). Coupled with galvanometric beam-scanning mirrors, this system allowed ablation shaping of transparent media, including poly(methyl methacrylate) (PMMA), collagen, and ex vivo porcine corneas. The surfaces of ablated structures were characterized using a noncontact confocal optical profiler. RESULTS: Spherical structures were successfully formed in all 3 materials tested. A 10.0 diopter refraction change in the cornea was produced in 180 seconds. The resulting surface quality was significantly higher (roughness length >100 microm versus approximately 6 microm) in gelatin and ex vivo corneas than in PMMA. CONCLUSION: The solid-state femtosecond UV laser system seems an attractive alternative to the currently used ophthalmic argon-fluoride excimer laser system because of its small footprint, silent operation, and ability to generate femtosecond light pulses at both 1027 nm (suitable for flap creation) and 205 nm (corneal ablation).