The t-Pulse series of femtosecond oscillators are the first commercial lasers to take full advantage a new class of laser materials, using Ytterbium as dopant. Ytterbium doped laser materials can be directly diode-pumped, thus eliminating the need for an intermediate pump laser used in traditional Titanium:Sapphire lasers. They also offer a number of attractive properties, such as a very high thermal efficiency, and the capability to generate femtosecond pulses with a high average power. The result is a family of compact and reliable lasers, with high average power, exceptional energy per pulse and excellent pulse-to-pulse stability. The latest model in the t-Pulse series delivers an unprecedented 500 nJ of energy, the highest value ever offered from a commercial femtosecond oscillator. Ultrashort pulse duration, as low as 40 fs are also available.