Scalable collinear BiB3O6 OPA for few-cycle CEP stable pulses at 2.1 µm

The authors present first results from a collinear OPA, yielding 180 μJ energy, CEP-stable, few-cycle pulses at 2.1μm without any post compression. The pulse duration and CEP after the first stage were measured with interferometric third order autocorrelation to 22 fs. Our approach is inherently scalable to higher energies making it an excellent route to high-repetition rate long-wavelength mJ-level few-cycle pulses, an ideal source for strong-field physics experiments such as high-harmonic generation in the water window.