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:YVO₄ 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.