Pushing the tuning limits of femtosecond Yb-based solid-state lasers to 1 µm: a Yb:YVO4 laser tunable down to 1004 nm

We have obtained what we believe to be the shortest fs tuning wavelength (1004 nm) from a Yb-based solid-state laser system. As the working horse, we have chosen Yb:YVO 4 due to its blueshifted gain spectrum. While using a single 10 W 952 nm diode for pumping and a semiconductor saturable absorber mirror (SESAM) for mode-locking, we have achieved 266 fs long pulses with up to 1.24 W of output power around 1021 nm. Using an intracavity birefringent filter, the central wavelength of the fs pulses could be tuned smoothly between 1004–1038 nm and 1009–1061 nm while employing the E//a and E//c axis of the material, respectively. By using an additional hard aperture to increase the modulation depth, we have also attained 100 fs level pulses in the 1012.5–1019 nm range, which shows the suitability of the system in seeding cryogenic Yb:YLF-based amplifiers.